Red Emerald

'Red emerald' is an old trade name for red beryl, the rare manganese-coloured red variety of the mineral beryl. Gemmological bodies discourage the term because the stone is not emerald — emerald is specifically the green, chromium- or vanadium-coloured variety of the same species — but the name persists in the gem trade for marketing.

What it actually is

The material is identical to red beryl: hexagonal beryl (beryllium aluminium silicate), hard at 7.5–8, occurring as small sharp red crystals. It is prized for its intense colour and extreme rarity.

Occurrence

Unlike most beryl, which forms in pegmatites, gem red beryl crystallises in cavities in topaz-bearing rhyolite. The Wah Wah Mountains and Thomas Range of Utah are effectively the only commercial sources, which is why cut stones above a carat are vanishingly rare.