Black Star Aquamarine

Gemological literature describes this type of beryl from Brazil, where oriented ilmenite inclusions in pale green aquamarine from Governador Valadares give a brown body colour and sheen, and from the Conco mine in the Alto Ligonha pegmatite region of Mozambique, sold as "black beryl". Star black beryl beads examined in 2023 had been bought from a Chinese e-commerce platform; their mine origin was not stated.

Under magnification the material is very light blue aquamarine with black inclusions lying in planes perpendicular to the optic axis, surrounded by brown clouds of colour. In 2023 a gemologist tested star black beryl beads sold as "Devil Blue" aquamarine: spot refractive index 1.57, specific gravity 2.67 to 2.73, inert to UV light and no diagnostic absorption spectrum, with Raman analysis confirming beryl. Three sets of needle-like inclusions perpendicular to the c-axis produce the star; layers of these needles also form parting planes. Because the trade name says "aquamarine" while the stone looks black, testing (refractive index, specific gravity, Raman) is the way to confirm it is beryl rather than another black stone.

Brown beryl with oriented ilmenite inclusions from Brazil was described in gemological journals in the mid-1950s, including by John Sinkankas (1955) and W. F. Eppler (1958), who documented a Brazilian brown beryl showing asterism. Mozambican "black beryl" pebbles were offered at the Tucson gem show in 2002, and star black beryl beads appeared in online retail by 2023.