gems, Arabic mineralogy, al-Biruni

Surveys medieval Islamic contributions to geodesy, geology, mineralogy, geography and cartography, emphasizing Ibn Sīnā, al-Bīrūnī and al-Khāzinī. Discusses measurements of the Earth, explanations of mountain and mineral formation, erosion, sedimentation and fossils. Of particular gemological interest are accounts of hydrostatic balances and measurements of gemstone and metal densities, illustrating the role of observation and experiment in distinguishing materials and assessing their purity.