Minerals and Metals in Ancient India v2.c43.s4.3

v2.c43.s4.3

In the case of samples supposed or expected to be diamond, specific gravity was considered an important property in view of the possible contamination with heavier minerals such as zircon. But it is doubtful whether accurate measurements of the specific gravity of gems were made in anicent India. Al-Biruni attempted some measurements (S.M.R. Ansari, ‘On the Physical Researches of Al-Biruni’, In Indian Journal of History of Science, Vol. 10, No.2, November 1975, pp. 198-217). The phenomenon of birefringence dvichāyā was known, but the concept of refractive index had not yet been evolved.