Varahamihira and Buddhabatta detailed the prices, qualities and defects of jewellery in their time. Several medieval books on gemmology still exists in India. For example the Chalukya king of 600 AD, Someswaradeva III and the Raja Balava of Keladi wrote on the methods to grade gemstones and of their value in the marketplace. Another gemmologist Thakkura Pheru became interested in gemstones when he became an assay master in the mint of the king Qutubuddin Shah of the Delhi Sultanate. These books wrote by ancient indian kings are still used by gemmologiest and jewellers in north india. In these books mentioned about a vast collection of gems that Alauddin won in his campaigns across india. He wrote in his books as follows;
The boxes were full of valuable gemstones, the excellence of which drove the onlookers mad. Every emerald sparked in the light of the sun, or rather the sun reflected back the light of the emerald.