A hand-held flashlight reveals the green color of a rough emerald from the Coscuez Emerald mine in Colombia. Photo by Eric Welch/GIA. Emerald is the green to bluish green variety of beryl, a mineral ...

Bengal International Jewellery Show, east India's largest B2B jewellery exhibition, continues the pursuit of displaying "Calcutta Handcrafted Jewellery" to the world, providing new horizons for the ...

The heat-induced conversion of limonitic residues to hematite in surface-reaching inclusions provides another useful clue to heat treatment in corundum. Because this alteration happens at such a low ...

This large Australian light opal cabochon weighs 117.85 carats. Small play-of-color flashes of orange and green predominate in a pinfire pattern, with spots of a more muted blue over a grayish ...

As a consumer, you will regularly encounter in the marketplace gems that have been treated to change their appearance. A topic that often comes up is whether a particular gemstone is or isn’t treated.

GIA IT will be performing maintenance on our internal systems from Friday, October 18th (5 PM PT) to Saturday, October 19th 2024 (8 PM PT). During this maintenance window, the My Lab application, ...

If you were born in February, your birthstone is amethyst – the purple variety of quartz that has captivated mankind for millennia. Its lilac to deep purple hues can be cut into many shapes and sizes, ...

GIA iD100 ® は、色の範囲が無色からほぼ無色、サイズが直径0.9ミリメートル以上のダイヤモンドにおいて、石留めされたものおよび裸石、原石およびカット済みの天然ダイヤモンドを ...

T Si: T-site Si atoms per formula. YZ R 2+: Y+Z-site total divalent cation. Otherwise the tourmaline belongs to alkali subgroups 3, 4, or 5, which are not considered here. Alkali subgroup 1 If Al 3+ ...

If you were born in the month of June, you are lucky enough to have three birthstones to call your own. June is one of only three months (the others are August and December) that has three birthstones ...

To address concerns about laboratory-grown and treated diamonds being mixed into parcels of melee, GIA has developed an automated system to analyze and sort melee-size diamonds quickly and accurately.

The best ametrines show distinct areas of orangy yellow and purple. These colors are featured in this graceful cut design. Photo by Lydia Dyer, © John Dyer & Co ...