Articles

Mottled fissures and planes provide evidence of heat treated spinel.

A mobile bubble floats in a cavity in spinel.

This article traces the development of the modern gemological laboratory from 1925 to the present date, a 100-year journey that has seen not just a gradual and then explosive evolution in the application and maturity of the science, but importantly the standing that gemological laboratories have enjoyed within the gemstone industry and the scientific community. The passionate people involved have made tremendous contributions to the understanding of gem materials and their willingness to embrace the latest technology as well as attract successive generations to the field has made the study of gem materials within gemological laboratories one of the most exciting theatres of life.

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.

Throughout the history of gemology, quartz has been a main target of gemological microscopists. A detailed study of the wide variety of inclusions in quartz is as complex an earth-science related mental exercise as any gemologist would ever care to undertake. This is not surprising, as quartz occurs in a wider range of geologic environments than any other mineral species, and the inclusions it holds testify to this.

East Africa's Mozambique orogenic belt stretches from Eastern Antarctica through East Africa to the Arabian penninsula. The highly mineralized zone is the source of many rich gem deposits, one of which is detailed in this article.

Gemmology in China has existed for many millennia, but has undergone rapid change and development in the past three decades. Today China is training more gemmologists than the rest of the world combined and has become the leader in the field.

An introduction to the articles in this special issue of the Chinese Journal of Gems & Gemmology, edited by Lotus Gemology's Richard W. Hughes and first published in May 2026.