[Pramāṇa](https://indike.org/pramana/) › [Studies](https://indike.org/pramana/ins) › [Science, technology and education](https://indike.org/pramana/ins.science) › [Minerals and Metals in Ancient India](https://indike.org/pramana/ins.science.biswas-1996) › v2.c45.s8.4 # Minerals and Metals in Ancient India v2.c45.s8.4 Minerals and Metals in Ancient India v2.c45.s8.4 - **Language:** English ### [v2.c45.s8.4](https://indike.org/pramana/ins.science.biswas-1996.v2.c45.s8.4) There are six varieties of \*tīkṣṇam\* (5.76). The \*khara\* variety is hard, breaks on bending, free of \*pogaras\* (hair follicles or hair-like lines) and on fracture, exhibits mercury-like shining surfaces (5.77). The \*sāra\* variety, ‘obtained from white earth’, has \*pogaras\* and its edges can be destroyed quickly (5.78). The \*hṛnnāla\* variety is whitish black, has \*pogara\* and is hard to pierce (5.79). The brittle variety looking like hair follicle is known as \*aṅga/vaṅga/pogara/tārāvaṭṭa\* (5.80). \*Vājira\* looks greyish black, and is full of hard \*pogaras\*, overspread by dense thin linings (5.81). \*Kālāyasa\* is bluish black, dense, smooth, bright, and its sharpened edge is not spoiled by hammering (5.82). These \*tīkṣṇa\* varieties are hundred times better (\*śatottaram\*) than other non-\*tīkṣṇa\* varieties (5.83). - [Previous: v2.c45.s8.3](https://indike.org/pramana/ins.science.biswas-1996.v2.c45.s8.3) - [Next: v2.c45.s8.5](https://indike.org/pramana/ins.science.biswas-1996.v2.c45.s8.5) - [Up: v2.c45.s8](https://indike.org/pramana/ins.science.biswas-1996.v2.c45.s8) ## Cites (1) - [Rasaratnasamuccaya](https://indike.org/pramana/in.med.rasa.samuccaya.pramukha.rasaratnasamuccaya.5.76) — Vāgbhaṭa (alchemist), Sanskrit --- Source: [https://indike.org/pramana/ins.science.biswas-1996.v2.c45.s8.4](https://indike.org/pramana/ins.science.biswas-1996.v2.c45.s8.4) · Pramāṇa