Great Indian mathematician and astrologer of the yore, Varahmihir has written profusely about the gemstones in his famous treatize Vrihatsamhita.
Following is the names of the gemstones described in Vrihatsamhita.
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- Vajramani (Heera) Diamond.
- Padma r
- Vimalak.
- Marakat (Panna) Emerald.
- Vaidurya (Lahsunia) Cat's eye.
- Sphatic (Rock Crystal)
- Sangandhik.
- Indraneel Mani (Neelam) Blue Sapphire.
- Rudhir.
- Raja Mani.
- Gomed (Gomedak) Hassonite.
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- Pushprag (Pukraj) Yellow Sapphire.
- Mukta (Moti) Pearl.
- Samyak.
- Shankh.
- Karkotak.
- Pulak.
- Shashikant.
- Mahaneel.
- Jyotiras.
- Brahmin Mani.
- Praval (Munga) Coral.
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Thus, only twenty-two gemstones have been described in Vrihatsamhita. You may ask: Why? It can only be said about it that during the period of Varahmihir only these twenty-two gemstones could have been in fashion.
OPAQUE GEMSTONES
Many elemental impurities that are present in the crystal lattice of a gemstone not only increases its density but also makes it opaque to light. Though presence of these impurities does not affect the utility of the stone. Akik and Phiroza (turquoise) are the famous example of opaque gemstones. These two stones are regarded particularly miraculous.
TRANSLUCENT GEMSTONES
These fall between the transparent and opaque categories. Many important gemstones come under the category of translucent stones. These stones are not as clear as the transparent stones nor as filthy as the opaque ones. Hence, the translucent gemstones can aptly be described as dim gemstones.
Regardless of the category, gemstones have more importance than the ordinary stones and are hence more in demand despite their high value. To be valuable a gemstone should fulfill some conditions like smoothness, better cut, brilliance etc. Apart from these hardness is another condition that a gemstone should comply to be designated as a jewel. Gemstones are invariably harder than the ordinary stones.
HARDNESS OF THE GEMSTONES
Composition of the chemical compounds, their mixture, relative density, crystal lattice etc. together determine the hardness of a gemstone. Since the chemical composition varies from stones to stones hence each and every gemstone has its unique hardness which commonly does not match with that of the other. Hardness is the main property of a gemstone. Diamond is the hardest gemstone. In fact, it is the hardest substance in the world. Besides it, emerald, blue and yellow sapphires and ruby are also hard. Coral is also hard but interestingly it is not a true stone. It is in fact a fossil and organic in origin.
Next to hardness it is specific density that differentiates one gemstone from another.
SPECIFIC DENSITY OF THE GEMS
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Gemstone
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Sp.Density
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TOPAZ
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3.53
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DIAMOND
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3.52
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HASSONITE (AGATE)
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4.20
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SPINEL
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2.15
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OPAL
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2.60
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ROCK CRYSTAL
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2.65
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AQUAMARINE
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2.74
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TURQUOISE
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2.82
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MOONSTONE
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2.87
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PARIDOT
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3.40
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GAMET
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4.07
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