From Anthroposophy
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Mineral substances such as metals exist not only as dense substance on the surface of the Earth, but also in the interior of the Earth, and in extreme high dilutions (see potentization) in the air and atmosphere and in Water, and hence also in the fluids that make up eighty percent of the Human physical body.

On and below the Earth surface metals exist in their rigid forms, down below in the Earth core they are in a fiery fluid condition. In the Earth's atmosphere they exist in a finely-divided state where the continuously radiate out into space and the cosmos, where they proceed to a certain boundary and return. This way metals are backwards raying onto the Earth.

At high temperature metals become fluid and give off fumes, and during the process throw off a super-homeopathic part which passes over continuously in 'universal invisible life' (that also acts on Man - see formative forces and Spectrum of elements and ethers).


  • metals speak, in a language related/similar to that of the dead (1923-11-30-GA232), they speak
    • a) in one form or the ordinary language of metals, they instruct Man about the experiences of the Earth in previous planetary stages,
    • b) in another form which is more poetic, related to the relationships between metals and Man, as a basis for curative properties and therapy
  • metals in Man
    • lead is necessary for Man to be a conscious being, not suffer unconsciousness through continual sprouting, growing. Without lead Man would not be able to think about our sense-perceptions, nor should we be able to preserve the memory of them. This capacity is given us by the finely divided lead in our brain. (1923-11-30-GA232)
  • in the evolution of the solar system, the substances that are now metals were spread out as part of the planetary spheres, upto were we currently have the boundaries of the orbits of the planets. On Earth they condensed down to physical matter and the mineral element earth, they were 'enchanted'. (1923-12-01-GA232 - compare with Schema FMC00.172 below, and also with Schema FMC00.142
  • in ancient times, when Man's physical constitution (and blood) was very different, it was normal practice to induce other states of consciousness by administering highly potentized (homoeopathic) doses of metals assisting people in their spiritual exercises. Rudolf Steiner gives the example of copper, and points to the Chaldean age (some 4-5000 years ago), stating these practices were still performed until the middle ages, but today don't make sense any more and would not work (1924-08-14-GA243)
  • see also Healing with metals


Schema FMC00.172 elaborates on the simpler FMC00.172A (see: Force substance representation). It shows how on physical Earth, coarse substance is 'Matter', and fine substance becomes 'Force', in the language of physics in mineral science. However between coarse substance (atoms) is the fine substance (ethers, force), and both form a balance that sustains itself, a bit like an extension of the phase diagram in chemistry.


Lecture coverage and references


synopsis includes: The Crystal Covering of the Earth — The Speech of the Metals — The backward-raying Forces of the Metals, and the Connection between Earth-lives.

That is the first acquaintance which man makes by means of Imaginative cognition when it is applied to the hardest part of the earth's surface.

We can make further progress in this knowledge if we go somewhat deeper into the earth and learn to know all that is in the interior of the earth, in veins or lodes of metal, or anything of a metallic nature generally. Here we penetrate under the surface of the earth; but here, when we meet what is metallic we come to something quite special, to an existence separate from the rest of the earth. Metals have something of an independent nature in them, they can be experienced as something independent; and this experience has much, very much to do with Man.

Even one who has already attained a certain higher knowledge by Imaginative vision is not yet quite at home when he experiences the quartz and other rocks of the primeval mountains in such a way that by becoming one with the million eyes of the earth he himself lives, feels and projects himself in experience into the whole cosmos. When, however, such a man approaches the interior of the earth there come to him the first impulses which accompany such a wonderful and deep experience as he may have in the stimulus to be had in a mine. Once, however, these impulses have come to him he only requires spiritual vision to be able everywhere to enter into relationship with that which is metallic, even if he does not go down into the borings of the mine.

But the first feeling of which I am speaking may be acquired with special intensity in metal mines. Even metal miners (though this is not so much the case as it was a few decades ago) who have inwardly grown up with their calling show something of what we may call a deep sense of the spiritual element in metals; for the metals not only perceive the environment of the cosmos but they speak, they speak spiritually. They relate things, they speak to us. And they speak in such a way that this language which they utter is very like that which one receives as an impression in another domain also.

[communication with and language of the dead = language metals speak]

When we succeed in setting up a psychic connection with human beings who are going through the development between death and re-birth (I have often mentioned this point before) we require for this a special language. The utterances of spiritualists are indeed childish in this domain for the reason that the dead do not speak the language of earthly man. Spiritualists believe that the dead speak in such a way that one can write down what they say, just as one may receive a letter from a contemporary, living here on the earth. For the most part it is high-flown matter that comes from spiritualist sittings, but even among our living contemporaries on the earth high-flown things are also written. But that is not the question here.

The first necessity is to find the right approach to the language which the dead speak, which has no resemblance to any language on earth. It certainly has a vocal-consonantal character but not like that of earthly speech. This language which can only be perceived by the spiritual ears is spoken also by the metals in the interior of the earth. And this language through which man can approach those souls who are living between death and re-birth relates to us the memories of the earth, the things that the earth has experienced in its passage through Old Saturn, Old Sun and Old Moon. We must let the metals relate to us what were the experiences of the earth. The experiences of the whole planetary system (I have already spoken of this) are told us by that which Old Saturn has to communicate to the planetary cosmic system in which we live. What the Earth has undergone in the process, of this the metals of the Earth speak.

The language spoken by the metals of the earth can assume two different forms.

  • When this language has the ordinary form, so to speak, there appears before us what the earth has gone through in its evolution beginning in the Old Saturn stage. What you find in my Outline of Occult Science regarding this evolution originated for the most part, in the way I have often described, through direct spiritual perception of the events. That is a mode of acquiring knowledge of these earth processes which is somewhat different from the mode to which I am now referring. For the metals speak more — if I may express myself thus; it is of course somewhat oddly expressed — the metals speak more of the personal experiences of the earth. They speak of what the earth has experienced as a cosmic personality. Thus, if I were to take into account the narratives of the metals, to which one can listen by penetrating spiritually into the inner part of the earth, I should have to add many details to what I have written about the Old Saturn, Old Sun and Old Moon stages, etc.
    • The first thing, for example, would be that those forms of Old Saturn which you will find described in my Outline of Occult Science as forms which consist in differentiations of heat would appear as powerful gigantic beings consisting in heat; beings of heat who, even as early as the Old Saturn stage, had reached a certain density. If such a thing could be (of course it is impossible, but let us suppose it could happen) that an earthly man were to meet these beings, he could become aware of them, he would be able to lay hold of them. At a certain time, about the middle of this Old Saturn stage these beings were not merely spiritual beings but they also displayed a physical existence; if a man had touched them he would have been blistered. It would however, be a mistake to suppose that these beings had a temperature of millions of degrees of heat. That is not the case, but they had inwardly such a temperature that if one could have grasped them the contact would have caused blisters.
    • As regards the Old Sun stage we should have to relate how in these formations described in my Occult Science as present in the Old Sun stage other beings appear, displaying wonderful transformations, wonderful metamorphoses. From gazing at, from observing these self-transforming beings one receives the impression, for instance, that the metamorphoses described by classical authors such as Ovid have something to do with these communications imparted to us, naturally indirectly, by the metals. Ovid was certainly not himself capable of directly understanding the language of the metals, and what he describes in his Metamorphoses does not perfectly correspond with the impression which one receives; but in a certain sense the correspondence is conveyed. .. [also note on Paracelsus] .. What could be learned in the mines in Asia Minor through the language of the metals was studied very deeply by Pythagoras, for example, on his wanderings, and from thence much penetrated into what became the Greek and Roman civilization. Then it appears in weakened form in such writings as Ovid's Metamorphoses. That then is one form of the language of the metals in the interior of the earth.
  • The other form — grotesque as it sounds, it is nevertheless true — the other form is that in which this speech of the metals begins to develop cosmic poesy, when it passes over into poetic form. There actually appears in the language of the metals cosmic fantasy. Then there resounds out of this cosmic poetry that which constitutes the most intimate relations between the metals and man. Such intimate relations between man and metals indeed exist. The coarse relationships of which physiology is aware relate only to a few metals.

It is known, for instance, that iron plays a great part in human blood; but iron is the only metal of this kind that does this. A certain number of other metals such as potassium, calcium, sodium, magnesium, also play a certain role, but a larger number of important metals, important for the structure and functioning of the earth, apparently play no part in the human organism, according to coarse external observation. But this is only apparently the case. When we go down into the earth and there learn to know the colour of the metals we also learn that metals are by no means confined to the interior of the earth, but are everywhere in the surroundings of the earth, though certainly in an exceedingly diluted form — I must here use the expression — in a super-homeopathic dilution they are distributed everywhere in the environment of the earth.

[lead in Man]

Roughly speaking, we can have no lead in us, but speaking more accurately, we cannot exist without lead. What would become of man if lead did not work upon him from the cosmos, from the atmosphere; if in an infinitely finely divided state lead itself did not penetrate through his eye with the nerve-sense ray; if lead did not penetrate into the body through the breathing and in an endlessly finely-divided state enter into us through food? What would man be if lead did not work in him?

Man would indeed have sense-perceptions without lead. He would perceive colours, he would perceive sounds; but in his perceptions of colours and sounds it would be as if, with every perception he became slightly unconscious. He would never be able to withdraw from his perceptions and reflect in thought, or form concepts of what he had perceived. If we did not take lead, as I have said, in super-homeopathic dilution into our nervous system and most of all into our brain we should be given up entirely to our sense-perceptions as to something outside of us. We should not be able to think about our sense-perceptions, nor should we be able to preserve the memory of them. This capacity is given us by the finely divided lead in our brain.

If lead be introduced into the human body in large quantities it results in the terrible lead-poisoning. But he who knows the connection can see from this lead-poisoning that, while lead when introduced into man's body in large quantities works excessive harm, in this fine super-homeopathic dilution it is something which causes as much to die off in man each moment as is necessary in order that he may become a conscious being, and not suffer unconsciousness through continual sprouting, budding, growing. For in sprouting and budding, in the over pressure of the pure forces of growth man becomes powerless.

It is thus that man is connected with all the metals, even with those concerning which our coarse physiology does not speak. The knowledge of these connections is the basis for a positive genuine true therapy; but instruction concerning these connections between the metals and man can only be given in that language which is the poetic speech of the metals in the earth.

Thus it may be said that

  • concerning the past experiences of the earth itself the ordinary language of the metals instructs man;
  • but the metals instruct man concerning their curative properties when they become poetic, when their language becomes poetry.

This is indeed a noteworthy connection. From the cosmic aspect, medicine is cosmic poetry; indicating how many secrets of the world are contained in the fact that something which on one niveau of the world is harmful and brings about disease, on another niveau is most beneficent, most perfect, most beautiful. This is shown us when Inspired cognition penetrates to the veins of metal in the earth, and to all that is metallic in the earth.

[metals subject to nature forces]

We may enter into another relationship with the metals, that relationship which becomes apparent when they are subjected to the forces of nature, for instance, to, fire or similar natural forces.

[antimony as example]

Observe the remarkable form assumed in the earth by antimony, a metal. It is composed of single spikes, which shows that when it is being formed it follows certain directions of force which are operative in the cosmos. This grey antimony has also the property that if it is heated and spread on glass it forms a mirror. Antimony has also other characteristics, for instance, that of exploding if it is treated electrically in a certain way and then brought to the cathode (the negative pole).

All these characteristics of antimony show the relation of such a metallic substance to the forces of the earth and its environment. This however, can be noticed in the case of all metals.

[matter at high temperature -> highly diluted -> part of formative forces]

We can observe all metals when they are subjected to fire, and we see how, if ever a higher temperature is developed they pass over into that super-homeopathic condition and at this high temperature take quite a different form. In this respect the ideas of our modern physicists are the most limited one can imagine. For example, they imagine that when they melt lead it becomes softer and softer, and of course that is quite correct as far as it goes. It does become softer as the temperature grows higher; the lead becomes hotter and hotter. It becomes more fluid until it gives off lead fumes. But all the time something is being thrown off that does not go beyond a certain temperature. This they do not know. It is just this finest, this super-homeopathic part of the lead which passes over continually into what I may call universal invisible life, and this is something which acts upon man.

[radiation from Earth to cosmic space and backwards raying]

The matter may be presented thus. In the earth down below you have the various metals, but these metals exist also in a finely-divided state everywhere above. I might say that these metals vapourize. Down below in the earth we have the metals with their sharp contours, with their rigid forms, and still further down they would certainly be in a fiery fluid condition. But in the environment of the earth they exist in this finely-divided state; there they reveal themselves in continual radiations so that a constant radiation goes out into the cosmos. The metals ray forth into space; but there is a certain elasticity in this cosmic space, and the forces which go forth in this way do not radiate without limit into space as the physicists imagine to be the case with light rays. They proceed to a certain boundary and then return.

[Walking Speaking Thinking (WST)]

One can observe this radiating back of the metals returning in all directions from the periphery of the cosmos as if they came from everywhere. One notices that these back-raying forces are active in that sphere of human life which is really the most wonderful and beautiful, that is, when, in the first years of its life a child learns to walk, speak, and think. The way in which a child raises itself from the crawling position to get its bearings in the world is really the most wonderful thing we can observe in earthly life — this realization of itself as a human being. Inwardly, in these forces which I have so often described work the backward-raying forces of the metals. While the child learns to raise itself upright from its horizontal crawling position it is permeated by these metallic forces which are being reflected back. It is these forces which really raise the child up.

[link with former earth lives]

If one can inwardly perceive and understand this connection, then at the same time one has another experience. One learns in his actions and in his being the connection of man as he lives here on the earth with his former earth lives.

It requires the same capacity to perceive the workings of metals in the cosmos as it does to perceive the karmic connection of successive earth lives. These capacities are the same, the one arises with the other, and the one does not exist without the other. For this reason I said in a different connection that in the power of orientation, in the raising itself of the child from crawling to standing upright and walking, in learning to speak and in learning to think lies that which comes over from former earthly lives. Anyone who has a feeling for these things can see in the way a child makes its first steps, in the way it walks, whether it has the inclination to press more on the toes or the heel, whether it bends the knees more or less strongly — in all this anyone who has an eye for these things can see a karmic tendency from a former earth life. This reveals itself primarily in the gait and it can now be perceived because the capacity to see the backward-raying forces of the metals and the power to observe the connection of man with his former earth lives belong together. ...

.. Some weeks ago I told you how, by observing the way a child or a man walks — whether he first raises his toes or his heel, whether he treads lightly or firmly, whether he bends the knees or holds them stiffly, etc. — that in all these things one can see the realization of his karma as the result of his former earth life. Today I have shown you how the reflected forces of the metals enable one to recognize how the several lives on earth are connected together.


synopsis includes: The Cosmic Memory of the Metals

.. there arises in man through the relationship with the metals an enhanced human consciousness which becomes an earth consciousness


Thus gradually, if we follow what is physical backwards through time we get away from the gross and elephantine, through the finer physical to the spiritual, and in this way, by paying attention to actual fact we get back to the spiritual origin of everything which belongs to the earth. The earth has its origin in the spiritual. That is the result of true vision, and I think it is a beautiful idea to be able to say:

If you penetrate into the interior of the earth, and let the hard metals tell you what they remember they will relate the following:

“We were once spread out in cosmic space in such a way that we were not physical substance at all, but in the spirit we were essence of colour, weaving in the cosmos, arising and vanishing.”

The memory of the metals of the earth takes us back to that condition where the metals were cosmic colours, permeating one another, where the cosmos was in essential a kind of rainbow, a kind of spectrum, which then gradually differentiated itself and then became physical.

This is the point at which what I may call the merely theoretical impression communicated by the metallic element of the earth passed over into the moral impression. For each metal tells us at the same time:

“I originate from the expanses of space and from earth-forms. I arise out of the heavenly kingdom. I am here drawn down and enchanted into the earth. But I await my redemption, for I shall once again fill the universe with my being.”

When in this way we learn to understand the speech of the metals, then gold tells us of the Sun, lead tells us of Saturn, copper tells us of Venus.

And then these metals say to us:

“Once upon a time we extended far out, copper to Venus, lead to Saturn. Today we are enchanted here. But when the earth shall have so fulfilled her task that man shall have attained what only on the earth he can attain we shall extend out yonder again. We have been enchanted in this way so that man on the earth might become a free being. When freedom has been purchased for man, then our disenchantment too can begin.”

This disenchantment has already begun. We have only to understand it. We must understand how the earth, together with man, will develop further into the future.


synopsis includes: The Secret of Plants, of Metals, and of Men.

When the pupil had been made sufficiently acquainted with the secrets of the moon, revealed to him by the plants growing out of the earth, he was led on further to the metals of the earth, to the principal metals, Lead, Tin, Iron, Gold, Copper, Quicksilver, Silver, as I explained to you in the last lecture in a different connection. When he had developed such an intensified life of feeling as I have indicated, he then made himself acquainted with the metals, and experienced what they so mysteriously relate; and through the metals he experienced the secrets of the entire planetary system. For lead told him about Saturn, tin about Jupiter, iron about Mars, gold about the Sun, copper about Venus, quicksilver about Mercury, and again silver about the Moon, in so far as she does not stand in close relationship with the earth, but belongs to the whole cosmos. Just as the blossoms revealed their secret to the pupil, so now he learned the metallic secret. First he learnt the secret of the plants, secondly that of the metals.

This secret of the metals which was given in the Eleusinian Mysteries, through that mighty planetary globe which, as I described in the last lecture surrounded the male statue, this secret of the metals still formed part of the instruction given, even at the time of Aristotle; and in this secret of the metals there was revealed the secret of the planets. Man's feelings were not then so coarse as they are today. When he approached the metal lead it did not merely appear in its lead-grey colour to the eye, but the lead-grey made a peculiar impression upon the inner eye. In a certain sense the leaden-grey colour of the fresh metal lead extinguished the other colours, and he felt that he participated in this lead-grey metallity. He came into another condition of consciousness and experienced something different from the present. He was filled with a feeling, a mood, as if the whole pre-earthly period of the earth rose before him. It was as if the present were toned down through the lead-grayness. Saturn nature revealed itself.

As regards gold, we know that according to external analogies the ancients saw in gold a representative of the sun. That was in truth not merely an external play of analogy that the sun was regarded as something precious in the heavens and gold as something valuable on earth. Really, nothing is too stupid for the man of today when he wishes to regard the ancients as stupid. When man regarded the metal gold, with its self-contained shining yellow colour, its modest mien and yet proud standing in the world, he actually felt how this is related to the entire blood-circulation of man. He felt in the quality of gold: “Thou art within that, thou feelest thyself as part of that.” Through this feeling he came gradually to comprehend the nature of the sun; he felt the relationship of the quality of gold with that which works from the sun in the blood of man.

Thus he gained a perception of the entire planetary system by means of the different metals, and the pupil, who did not think about these things as intellectually as we do today, conceived the following formula:

I think about the metals;

They reveal their relationship with the planets

They are subdued by the earth; for they are born of the air.

Actually the metals which are today in the earth came out of the cosmos in an airy form, and only gradually became fluidic during the ancient Moon-period. They came over in airy form when the earth was in the ancient Sun-condition; they attained a fluid form during the Moon-period, and then they became subdued by the earth and reduced to solid form during the earth evolution. That was the second secret which was revealed to the pupil.


lecture titled: Form and Substantiality of the Mineral Kingdom in Relation to the Levels of Consciousness in Man


  • The mineral-crystal kingdom is created from the interplay of cosmic currents. The Gods are reflected in the crystals. Our soul should be filled with veneration and awe; our thought-life should not have an intellectual basis. With clairvoyant perception of the permeability of certain crystals we experience a revival of fear. At a later stage of knowledge we learn to know the “metallity” of metals as well as their crystal forms.
  • Meditation on Iron. Consciousness rises to the larynx. We enter the astral world and perceive the group-souls of the animals.
  • Meditation on Tin. Consciousness lies in the region between the eyes. We begin to leave our body and ascend into the Cosmos as far as the Jupiter sphere. The Iron consciousness embraces the Mars sphere, Gold the Earth sphere.
  • Meditation on Lead. We leave our body completely and rise to the Saturn sphere.
  • Meditation on Copper. The Copper consciousness pervades our whole being. It radiates from the centre below the heart and the ‘second’ man arises. He has emerged from Space into Time. He is awake in the world of the dead.
  • The ancient Chaldeans lived in the Iron (Mars) consciousness. They learned about life after death from Moon beings. Today this is no longer necessary.


  • The relationship of “metallity” to other forms of consciousness in man.
  • In ancient times it was customary to induce other states of consciousness by administration of metals internally, but only after years of training. This is no longer suitable today because the inner constitution of man is different. Today the method must be a spiritual one. The book Knowledge of the Higher Worlds indirectly gives indications for meditation upon metals.
  • Relationship between disease and consciousness. Disturbance of digestive functions indicates that copper consciousness is working too strongly in an unconscious manner in the world of the dead. Balance is restored by administering copper. This is the province of the medical practitioner. All substances have a physical and a moral side. The relationship between medical science and moral science must be renewed on a new basis.

When they hear, for example, that the qualities of certain metals are associated with other levels of consciousness, they feel more reassured. If a small dosage of copper is all that is required in order to preserve a spiritual link with another after death, then why not take it, they conclude, if it enables one to develop a higher level of consciousness.

The idea becomes all the more attractive when they hear that the practice adopted in the ancient Mysteries was not so very dissimilar, though in those days, of course, it was only carried out under the continuous and closest supervision of the Initiates. And when people are told of this, they wonder why these old practices are not revived. But they overlook the fact that in ancient times the whole physical organization of man was differently constituted. In those days, and even as late as the Chaldean epoch, he lacked our present intellectuality. Thoughts were not self-generated as today, but came to him through inspiration. Just as we realize today that we do not create the red of the rose, but receive the impression of the rose from without, so the men of ancient times were aware that thoughts were transmitted via external objects, they were “in-spired,” breathed into them. The reason for this was to be found in the different constitution of the physical organism, including even the composition of the blood.

Therefore it was possible to administer highly potentized doses of those metals I have spoken of — homoeopathic doses as we call them today — in order to assist people in carrying out their spiritual exercises.

A man of the Chaldean epoch, we will suppose, has been prescribed highly potentized doses of copper.

  • Before taking it — this was the general practice of the time — he was directed to perform certain specific spiritual exercises. In such cases, years rather than days of training were demanded of him before the highly potentized copper could be administered.
  • And because his physical constitution was different from ours, he learned, through his training, to retrace the reactions upon the upper part of the body, of this finely distributed, highly potentized copper that was circulating in his blood stream. When copper was administered after this careful training, he felt inwardly that his words took on added warmth, because he himself had generated warmth in his larynx and in the nerves leading from the larynx to the brain.

Now because his physical make-up was different, he was able to react with such extreme sensitivity to what was taking place within him. If one were to administer highly potentized copper in similar circumstances today, it would of course take effect, but it would provoke a laryngeal condition and nothing further.

It is important, therefore, to understand the difference between the physical constitution of man in those times and that of today. Then one will no longer be tempted to induce other states of consciousness by administering medicaments, which was the normal practice in ancient times and was still frequently practised in the Middle Ages.

At the present time the only valid method is for Man to have an inner perception of the nature, the essential being of copper as I indicated yesterday and thus develop a sensitive response to the colour of burnished copper, to the behaviour of copper in copper sulphate solution. By concentrating and meditating upon this response, he will ensure that he reacts in the right way.


It is necessary, therefore, to see things in their proper relationship, because it would be a mistake for the man of today to follow uncritically the methods of the ancient Mysteries in order to gain insight into the spiritual world. The right course for today is to replace the external, physical approach by a more moral and spiritual approach. With the development of his physical organism man's whole relationship to nature has been transformed. Composition of the blood, tissue fluid and the whole physical constitution are different today from those of the ancient Chaldeans. This cannot be proved by anatomical analysis. In the first place, the anatomist spends most of his time dissecting corpses. Recently a scientific congress raised a cry of alarm and clamoured for more corpses. Anatomists found there was a shortage of corpses for investigating the hidden secrets of life. But it would not be easy to procure Chaldean corpses in order to pursue these investigations! In the second place, with his crude technique, the anatomist would find no answer to the hidden secrets of life; these must be explored by spiritual means.

Since our physical body is differently constituted from that of the ancients, one point must be clearly established. It is still possible today to dispense highly potentized substances, metal potencies, for example. What is the reason for this? The explanation is that we have a deeper insight into the real being of nature. If we really understand the nature of the human body, we know that its functioning is modified by the metals I have mentioned — tin, copper, lead, and so forth. And I have shown how they modify, in the first instance, the conditions of consciousness.


Related pages

References and further reading

  • Wilhelm Pelikan: 'The secrets of metals' (1959 in DE, 1973 in EN)
  • Mellie Uyldert: 'Metal magic: the esoteric properties and uses of metals' (1980-82)
  • Leendert F. C. Mees: 'Lebende Metalle: Verwandtschaft zwischen Mensch und Metall' (1983 in DE, original in NL: 'Levende metalen. Weinig gebruikelijke gedachten over de relatie van materie en mens)
  • Alison Davidson: 'Metal power: the soul life of the planets' (1991)
  • Nick Kollerstrom
    • 'Astrochemistry: study of metal-plant affinities' (1984)
    • 'The metal-plant relationship' (1993)
    • 'The secrets of the seven metals' (2015)