Earth’s surface is divided into tectonic plates, and the ones that make up the ocean floor are destined to sink. Sheets of oceanic crust typically bend and sink down into Earth’s interior at so-called ...

Cuprian (copper-bearing) tourmaline, known as “Paraíba” tourmaline in the trade, has been an important gem since its discovery in 1989. Until now, almost all of the material reported has been ...

GIAは、Gübelin宝石コレクションの中から400以上の重要な宝石を研究しており、この宝石学的情報の宝庫を共有することに全力を尽くします。この研究は、すべての学生、宝石鑑別士、研究員 ...

Two pearls presented a unique challenge, as testing at three different gemological laboratories could not conclusively identify them as natural or cultured, determine a freshwater or saltwater growth ...

Courtesy of Tom Dodge CollectionThis 54.32-carat fire obsidian displays vibrant colors caused by thin-film interference. Light reflects off nanoscale layers of magnetite within the stone, and the ...

Rough pink diamonds are rarely found, and although the cause of color has been correlated with plastic deformation, the precise mechanism and atomic configuration for the resulting color are topics of ...

The Motswedi diamond weighed 2,488.32 carats (approximately 1.10 pounds!) upon arrival at GIA, along with 11 smaller fragments that had broken off, weighing a total of 1.50 carats. Two larger pieces ...

Explore diamond history, research, quality factors, and more in the GIA Gem Encyclopedia.

CARLSBAD, Calif. – June 2, 2025 – Beginning later this year, GIA (the Gemological Institute of America) will start using descriptive terms to characterize the quality of laboratory-grown diamonds and ...

These environmental stresses create a unique "fingerprint" within each natural diamond that is only visible under deep-UV light. Much like the growth rings of a tree, these patterns tell a story of ...

Since its discovery at the beginning of the nineteenth century, infrared light has proven to be a versatile tool for scientists, industrialists, and consumers. The gem industry has benefited from the ...

Industry analysts project that by 2025, 20% of all diamonds on the market will be laboratory-grown. Indeed, the gem industry has seen a significant increase in the quantity, size, and quality of ...