Minerals and Metals in Ancient India v2.c43.s3.t10: Feldspar Group of Gems

Minerals and Metals in Ancient India v2.c43.s3.t10

Language: English

Feldspar Group of Gems

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RAlSi₃O₈ represents the general group of feldspar minerals where R may be potassium (partly replaced by sodium) in orthoclase and microcline, or sodium (partly replaced by calcium) in plagioclase.

Moonstone, available in Sri Lanka, is a microperthitic to sub-microperthitic intergrowth of orthoclase and albite in an arrangement of thin layers exhibiting a pearly opalescent reflection or shiller or a delicate play of colours. It has a beautiful blue bloom and lovely sheen. Sunstone is a variety of oligoclase, Na-Ca feldspar containing little K and Ba feldspar. A play of colour (fire-red, yellow, blue, green etc.) is a common characteristic of sunstone; this is due to interference of light, caused by reflection from thin lamellar inclusions of various minerals such as hematite, goethite etc. Usually this mineral is associated with igneous rock.

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Nandaka and śītavṛṣṭi in AS, 2.11.31-32 could have been moonstone, which was mentioned as śaśikānta in Bṛhatsaṃhitā (Bṛ. Saṃ., 80.4) and Rayaṇaparikkhā (RYP, 96), and as candrakānta in other texts such as Navaratnaparīkṣā (NRP, 154 and 156), Ratnasaṃgraha (RS, 18) and Maṇimālā (MM, 436 and 438). The typical description of candrakānta is:

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पूर्णेन्दुकर्संस्पर्शात् अमृतं क्षरति क्षणात्। चन्द्रकान्ति तत् आख्यातम् दुर्लभम् स्यात् कलौ युगे।। pūrṇendukara saṃsparśāt amṛtam kṣarati kṣaṇāt | candrakānti tat ākhyātam durlabham syāt kalau yuge || (NRP, 156; MM, 438)

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That which runs nectar when the moon at its full bathes it with its balmy influence, is called candrakānta.

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Sanskrit literature is replete with ‘candrakānta slabs on which lovers in separation seek solace’. Could these be plain marble?

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The Ratnaśāstra texts (NRP, 154 & 156; RS, 18; MM, 436 & 438; RYP, 96) claim that candrakānta is a variety of sphaṭika or quartz. But we believe that candrakānta is a moonstone, a variety of feldspar defined earlier, which was available in Sri Lanka only. As it stands admitted in NRP, 156 (durlabham), it was rarely availble in India.

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Sūryakānta or Ravikānta (AS, 2.11.32; NRP, 154-155; RS, 18; MM, 436-437 and RYP, 96) could however belong to the quartz family as claimed in the above-cited literatures. We have earlier quoted NRP, 155: sūryāṃśusparśamātreṇa vahnim vamati which means ‘fire emerges when sun-rays pass through’, and implies that sūryakānta could mean a lens of tranparent rock crystal. Alternatively, it could be sunstone of the feldspar family as defined earlier.

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Hiuen Tsang (AD 629) mentioned about Yun-shih rock near the Tiladaka monastery in Magadha. It has been translated as cloud-stone or ‘variegated marble’ (Samuel Beal: Buddhist Records of the Western World, 1969, Book VIII, p. 103). It could be a siliceous rock as well.

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We may briefly comment on fine yellowish-green or golden yellow chrysolite (French jewellers call it peridot), which is precious olivine or a gem variety of the group of mineral called olivine R₁²⁺ R₂²⁺ (SiO₄) wherein R₁ and R₂ could be various combinations of Mg, Fe, Ca and Mn. Chrysolite contains more of Mg and Fe²⁺ accounting for the typical colour. Its hardness is 6-3/4; it is slightly softer than quartz and its specific gravity is 3.33-3.37, more than that of emerald. At present, the reserves of the gem probably stand exhausted, but in the ancient world, it was well-known and created some confusion with emerald (green) and topaz (yellow), all the three gem minerals occurring together between the Nile and the Red Sea. E.S. Dana has commented that ‘the chrysolithus of Pliny was probably our topaz and his topaz our chrysolite’. The two different materials could be easily distinguished in terms of their hardness, topaz being much harder.

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The above confusion between chrysolite and topaz was connected with the Sanskrit words: pita meaning yellow and pittaka meaning colour of bile what is green or greenish-yellow. Arthaśāstra mentioned a gem pittaka (AS, 2.11.35) which was most possibly chrysolite. Later, another name came up: ‘rucaka which is yellow, green, red or tawny, found in the borders of Kashmir’ (quoted by Tagore in Maṇimālā, pp. 508-9), and this also could be chrysolite. The Sanskrit word pita was converted to pittdoh in Hebrew and then to tipdoh and topazion. The confusion between pittaka chrysolite and pita topaz is now a matter of history.

Linked texts (2)

Kauṭilīya Arthaśāstra — Kauṭilya, Sanskrit
Bṛhatsaṃhitā — Varāhamihira, Sanskrit