A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v2.c32.s16: Knowledge of Gems
A History of Hindu Chemistry from the Earliest Times to the Middle of the Sixteenth Century A.D. v2.c32.s16
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Knowledge of Gems
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A few words on gems may not be considered beyond the scope of the present work especially as the subject has already drawn the attention of some European scholars.[*] We shall, however, limit ourselves, as far as possible, purely to the physical and chemical properties of the precious stones.
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It has already been seen that among the 64 branches of arts and sciences recognised in the ancient ‘Kāmasūtra’ of Vātsyāyana occur the following:—(a) the testing [of the genuineness or otherwise] of gold and the gems; (b) knowledge of the colouring of gems, as also of mines and quarries.[†] Varāhamihira (d. 587 A. D.) in his “Vrihat Samhitā” also conveys much useful information on this subject, but as he in his turn refers to experts who preceded him,* it may safely be concluded that long before this time it received adequate attention.
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∗ Garbe in his “Indischen Mineralien” (Leipzig, 1882) gives the text and the translation of Ch. xiii of Narahari’s “Rájanighantu”; this work, however, is comparatively modern. Much useful information on the subject with bibliographical references will be found in Professor Yogesa Chandra Ráy’s treatise in Bengali entitled “Ratnaparíkshá.”
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† Vide Vol. i, p. 191.
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The *Garudapurāna* under the heading of Ratnaparīkshā (examination of the gems) devotes several chapters to a detailed and fairly exhaustive description of the gems. This Purāna like so many of its class discusses on a variety of topics, mundane and spiritual ; in short, it may be looked upon as a sort of *multum in parvo*.
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From time immemorial the gems have been valued in India not only for purely decorative and ornamental purposes, but also as agents for warding off perils and the malignant influences of the planets and for securing luck and longevity. Hence it is that particular attention is paid to the testing of gems, as their virtue increases in proportion as they are faultless and flawless.
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The typical characters which were most relied upon for differentiating one species of a gem from another were (1) the relative weight, (2) hardness, (3) lustre, transparency and colour, (4) fusibility, especially when heated in combination with the alkalies. It will be noticed that even the lapidaries and the mineralogists of the present day have to depend largely upon these properties in the classification of the stones. We shall now proceed to say a few words under each of the above characters following in the main the authority of Garuda-purāṇa.
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∗ पूर्वाचार्यैः समुद्दिष्टं.
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1. RELATIVE WEIGHT. We have purposely used these terms as contradistinguished from "specific gravity": as the latter connotes peculiar associations. The principle of Archemedes being evidently unknown among the Hindus, the measurement of volume could only be roughly approximate. To cite some illustrations. A stone may be of the same species as, and equal in volume to, a padmarāga (oriental ruby), but will differ in weight from the latter.*
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Empirical and arbitrary scales of weight were adopted as standards. A ruby occupying the volume of a guñja (abrus precatorius) may be equal in weight to 10, 7 and 3 guñjas respectively. A ruby of the volume of a sṛgālakola (a kind of jujube) should weigh 12, 8 and 7 guñjas respectively. Again, a ruby of the volume of an āmalakī (phyllanthus emblica) should weigh 30, 20 and 16 māshās respectively.* In each case the gem which is of greater weight is superior in quality and the value thereof is enhanced in proportion.†
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∗ तुल्यप्रमाणस्य च तुल्यजातीयो वा गुरुत्वेन भवेन्न तुल्यः । Garuda.
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† Garuda lays special stress on the high specific gravity (=4·0) of a genuine ruby. लघुत्वं विजातिलिङ्गं, again गुरुत्वं मणीनां गुणसंग्रहः । While high specific gravity is indicative of the excellence of the gems in general, in the case of diamond it is just the reverse. गुरुता सर्व्वरत्नानां गौरवाधानकारणम् । वज्रे तत् वैपरीत्येन सूरयः परिचक्षते ॥ It is not easy to account for this qualifying clause, seeing that diamond has a sp. gr. of 3·5.
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In the case of precious metals, however, adulteration was detected by an ingenious device, which may be regarded as a near approach to the principle of Archemedes. Suppose it is intended to test the purity of a specimen of gold. All that one has to do is to draw a wire of this gold and another of the standard gold through the self-same orifice [of corundum]. As these wires are of equal
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∗ We give below the standard weights as current at the time of Varāhamihira.
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| 8 | White mustards | ... | = | 1 tandula (a grain of paddy) |
| 4 | Tandulas | ... | = | 1 gunja (abrus precatorius) |
| 5 | Gunjas | ... | = | 1 Máshá |
| 16 | Máshás | ... | = | 1 Karsha or suvarna or tolaka |
| 4 | Karshas | ... | = | 1 pala |
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The standard of weight has always varied in different times in different parts of India. 10 gunjas weigh about 18 grains. The seeds often vary in size.
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diameters, equal lengths will have equal weights, provided the sample is pure.*
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2. HARDNESS. There are many stones which in external appearance resemble a ruby; the spurious substitute may easily be detected by its difference in softness (low degree of hardness), and low specific gravity: again in case of suspicion the gem is to be rubbed on a whetstone; if it simply gains in lustre but does not lose in weight (by abrasion), the specimen is to be regarded as genuine (test of a ruby).† Diamond and corundum alone will scratch ruby and sapphire. Skilful lapidaries often make imitation diamonds of zircon, ruby, cat's-eye, rock-crystal and glass; hence they are to be tested by calling in the aid of learned experts. All the gems occurring in this world as also the metals will be scratched by a diamond, but the latter will not be similarly affected by the former . . . . . A diamond alone will scratch a diamond.‡
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† This is true in a qualified sense only. After the diamond corundum is the hardest of all known minerals.
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‡ The ruby and the sapphire are only varieties of corundum, Varāha classes corundum as a species of ruby, the former being dotted over with black and white patches and feeble in lustre [i. e. the non-transparent or coarse kind]. It is scarcely necessary to
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* एकच्छिद्रे समाकृष्टे समखण्डे द्वयोर्यदा ।
धात्वोः सूत्रं मानसमं निदिष्टस्य भवेत्तदा ॥ Sukranīti.
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∗ एकच्छिद्रे समाकृष्टे समखण्डे द्वयोर्यदा । धात्वोः सूत्रं मानसमं निदिष्टस्य भवेत्तदा ॥ Sukranīti.
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To the above tests Rājanighantu adds another, namely, when a diamond is struck with an iron hammer, it is not broken to pieces *
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point out that the very word "corundum" is derived from the Hindi kurand, a corrupt form of the Sanskrit kuruvinda. The statement "corundum will scratch ruby and sapphire" is not strictly accurate. There are degrees of hardness among the different varieties of corundum, the blue sapphire standing first in this respect.
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We give here the original texts of which we have given above almost a literal translation.
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स्नेहप्रभेदो मृदुता लघुत्वं विजातिलिङ्गं खलु सार्वजन्यम् ।
अप्रणश्यति सन्देहे शिलायां परिघर्षयेत् ।
घृष्टा योऽत्यन्तशोभावान् परिमाणं न मुञ्चति ।
स ज्ञेयः शुद्धजातिस्तु ज्ञेयाश्चान्ये विजातयः ॥
वज्रं वा कुरुविन्दं वा विमुच्यान्येन केनचित् ।
न शक्यं लेखनं कर्तुं पद्मरागेन्द्रनीलयोः ॥
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* The reading of the text is very corrupt. Garbe gives as many as 12 variants ; that adopted by him seems to be on the whole reliable as also his rendering : " Wenn er mit anderen steinen oder eisernen Hammern geschlagen nicht zerspringt." On account of its brittleness a diamond will readily be shivered into splinters under the blow of a hammer. The following extract from Bauer and Spencer's "Precious stones" (pp. 129-130) may prove of interest.—
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"The hardness of diamond has often been confused with its frangibility or brittleness. It has been supposed, especially in ancient and mediæval times that hammer and anvil may be shattered but the diamond which lies between. This statement was 3. LUSTRE, TRANSPARENCY, COLOUR and other optical properties. Difference in lustre (स्नेहप्रभेद) is often regarded as a diagnostic feature of the gems. According to Varāha gems of superior qualities should possess cool (lit. waxy) lustre, be limpid and emit rich rays. Classification according to colour is often enjoined. For instance, a diamond may be perfectly colourless, or it may be yellow,
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made by Pliny, the great naturalist of ancient days, who was killed in 79 A.D. at the first historic eruption of Vesuvius. He proceeded to say further that the fragmentation of a diamond may be effected by subjecting it to a preliminary immersion in the warm blood of a goat, but that even under these circumstances the hammer and anvil will also be broken! According to Albertus Magnus (1205-1280) the blood is more efficacious if the goat has previously drunk wine or eaten parsely.
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"Such being the views then held respecting the unbreakable and indestructible character of the diamond, it is easy to understand why the Greek word adamas, signifying unconquerable, should have been applied to this stone, although its application to the diamond is singularly inappropriate and inaccurate when its extreme frangibility is considered. Many a doubtful stone has been submitted to the test of the hammer, with the belief that the blow would be resisted only if the stone were a genuine diamond. Probably many beautiful stones have been sacrificed to this old belief. As a matter of fact, diamond is easily fractured, a very moderate blow from a hammer sufficing for the purpose; its perfect cleavage places it among the most brittle of minerals."
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black, red or copper-tinted.* Stones which are translucent, opaque and of dull colour are inferior in quality. In the case of diamond special stress is laid on its displaying the colours of the rainbow [due to its high dispersive power]. Some gems have only one shade of colour (एकच्छाय), others again two (द्विच्छाय).†
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† Probably refers to dichroism. As has already been pointed out the red ruby and the blue sapphire are only varieties of corundum, which often occur in well-developed crystals belonging to the rhombohedral division of the hexagonal system. "The dichroism of the ruby affords a means whereby it may be distinguished with certainty from other red stones, such as spinel and the different varieties of garnet, which crystallise in the cubic system, and thus being singly refracting can show no dichroism," (Bauer and Spencer). "The dichroism of the sapphires of Siam is specially well marked." —Ibid.
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The changes in colour which the ruby and the sapphire undergo under the influence of heat had evidently been carefully observed. This test is to be applied with extreme caution as in case the proper degree of temperature (अग्निमात्रा) is exceeded, the stone may be materially injured.*
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∗ रक्त पीतं सितं शैरीषं (Varáha); आताम्रं (Garuda). Yellow diamonds are unknown in India at the present day at any rate. "India can claim for its own all the finely coloured stones of blue, green and red, not however, yellow diamonds, which come mainly from South Africa." (Bauer and Spencer). Crystals of black diamond should not be confounded with the black carbonado.
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4. FUSIBILITY (LIQUEFACTION). It was well-known that all the gems with the exception of diamond would undergo liquefaction when strongly heated with a mixture of the two alkaline carbonates [now familiar in the Laboratory as the "fusion mixture"]. The liquid principle of gems रत्नजा द्रुति was a favourite remedy with the Hindu Iatro-Chemists (Cf. Vol. i, p 103). As most of the precious stones belong to the corundum and the spinel group, they easily yield to treatment with sodium and potassium carbonates. In the case of the pearls it is recommended that they should be enclosed inside lemons and placed in a mass of paddy grains {for the sake of the warmth}.
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* यावन्तं चक्रमेद्ग्निं पद्मरागपयोगतः (?) ।
इन्द्रनीलमणिस्तस्मात् क्रमेत सुमहत्तरम् ॥
तथापि न परीक्षार्थं गुणानामभिवृद्धये ।
मणिरत्नौ समाधेयः कथञ्चिदपि कश्चन ॥
अग्निमात्रा(ऽ)परिज्ञाने दाहदोषैश्च दूषितः ।
सोऽनर्थाय भवेद्भर्त्तुः कर्तुः कारयितुस्तथा ॥ Garuda.
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Cf. "The red ruby, at a high temperature, is colourless: on cooling it first becomes green, after which it gradually assumes its original fine red colour." (Bauer and Spencer). "The blue colour of the sapphire disappears on heating."—Ibid.
Linked texts (4)
- Garuḍapurāṇa — Vyāsa, Sanskrit
- Rājanighaṇṭu (Nighaṇṭurāja, Abhidhānacūḍāmaṇi) — Narahari Paṇḍita, Sanskrit
- Bṛhatsaṃhitā — Varāhamihira, Sanskrit
- Kāmasūtra — Vātsyāyana Mallanāga, Sanskrit