Minerals and Metals in Ancient India v2.c41.s4.18

v2.c41.s4.18

Jimutaprabha is probably cloudstone or faint bluish marble. Moonstone or candrakānta, an intergrowth of orthoclase and albite, with pearly opalescent reflection, blue bloom and lovely sheen (available in Sri Lanka), was probably meant in the Arthaśāstra’s nandaka (2.11.31) and śitavṛṣṭi (2.11.32). Sūryakānta, classified with sphaṭika or quartz (2.11.32), is clearly sunstone, which is sodium-calcium feldspar with strong optical interference, reflectivity and play of colour. Was Lord Kṛṣṇa’s famous syamantaka a sample of sūryakānta or vajra (diamond)?