There is also mention of another author in medieval period, Thakkar Pheru, who is again credited to have worked on this subject.
For the benefit of his son Hemapal, he wrote several books on related subjects including Dravya Prariksha on metals and various coins; and Ratna Pariksha on various precious gems stones.
Bharat Ratna | Tri-Ratna Secondary School | T Ratna Bai | Ratna Park | Ratna Pariksha |