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 ...

Blue color in aquamarine and yellow color in heliodor are attributed to abundant Fe ions (Wood and Nassau, 1968). Fe ions are also present in all other color varieties of beryl, though Fe content is ...

Blue zircon is perhaps best known from Cambodia, with most if not all of the material recovered as brown stones that turn blue upon heating. Recently, Brent Smith of Phoenix Gems supplied us with a ...

At the earth’s surface, graphite is the stable crystalline form of carbon, with a density of 2.26 g/cm 3. Diamond is a much more compact form of carbon, with a density of 3.52 g/cm 3, 56% higher than ...

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 ...

Once a gem is submitted: Your name or store info is removed, so analysis is completely unbiased. Every gem, whether from a local jeweler or a globally recognized brand, is evaluated using the same ...

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 ...

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 ...