Articles

Colorful mosaic-like inclusions in a heated orange sapphire reveal tiny thin-film decrepitation inclusions associated with high-temperature heat treatment.

Fluorescent diopside, phlogopite, and edenite inclusions in a spinel reportedly from Tanzania reveal identification clues under short-wave ultraviolet light.

Mong Hsu ruby is known for cottony diaspore 'silk,' but in rare cases another type of silk can be observed.

A parcel of opals shows tell-tale signs of smoke treatment.

In our social media polls, 87% of Instagram respondents and 96% of Facebook respondents thought this ruby was unheated.

Mottled fissures and planes provide evidence of heat treated spinel.

A mobile bubble floats in a cavity in spinel.

Abū Rayḥān Muḥammad ibn Aḥmad al-Bīrūnī was born in 973 CE, in what is now Uzbekistan. A polymath of the Islamic Golden Age, he distinguished himself in numerous fields, including medicine, astronomy, history, mathematics, physics, mineralogy, gemmology, encyclopedism, geography, philosophy, sociology, and travel. His vast intellectual contributions rank him among the greatest minds of any era. Al-Bīrūnī authored some 145 works, but tragically many of these are now lost. Given the sheer scale and depth of his intellectual legacy, any attempt to comprehensively study al-Bīrūnī’s contributions is inevitably limited and fraught with gaps. However, what we do know demonstrates that this was a remarkable man, on the order of an Aristotle or Einstein. And yet much of the world has never even heard of him. This paper will largely focus on his gemmological work, while also touching on his other accomplishments.

This article is a brief survey of the historical methods of describing and assessing the quality of coloured gemstones, tracing these from ancient times to the end of the 18th century. Examining historical texts and inventories reveals how features and flaws of gemstones were observed and used to determine their value. The article considers various historical periods, including the ancient world, medieval Muslim world, early India, and medieval Europe, highlighting the changing criteria and expertise involved in judging gems. This study demonstrates the historical depth of gem connoisseurship and its influence on modern gem assessment practices.

During the Qing dynasty (1644–1911), court artisans carved agates with a high degree of technical ability and inventiveness. Agate wares produced during the reign of the Yongzheng (1723–35) and Qianlong (1736–1795) emperors exploit the full breadth of chromatic effects and degrees of translucency offered by these silicate stones. During this period, agate carvings were produced in high numbers, and imperial commissions made conscious use of the stone’s unique material qualities. Because the geological environment in which agates are formed affects their pigmentation, the range of agate colors recorded in historical documents and seen in surviving objects reflects a variety of geographical origins. This paper considers how agates were understood by scholars and appreciated by emperors at a time of territorial expansion and interest in new minerals.