gems, Arabic mineralogy, history of science, al-Biruni, Islamic science, specific gravity, balance of wisdom

Khanykov presents an extensive analysis, translation, and series of extracts from al-Khāzinī’s twelfth-century Arabic Kitāb Mīzān al-Ḥikma [Book of the Balance of Wisdom], a major medieval treatise on hydrostatics, specific gravity, and the construction and use of balances. The work describes sophisticated balances designed for determining the relative weights and specific gravities of substances in air and water, discusses principles derived from Archimedes and earlier Greek and Islamic scholars, and preserves information from works otherwise lost or imperfectly known. Of particular gemological importance are tables and discussions of the specific gravities of minerals, metals, and precious stones, including ruby, sapphire, emerald, diamond, quartz, and other materials, together with methods for distinguishing substances through quantitative measurement. Khanykov compares al-Khāzinī’s results with those attributed to earlier investigators, notably al-Bīrūnī, demonstrating the high level of experimental precision achieved by medieval Islamic scientists. The paper provides one of the earliest substantial European-language accounts of The Book of the Balance of Wisdom and is an important source for the history of hydrostatics, mineralogy, and quantitative gem testing.