Sinhalite (MgAlBO4), a New Mineral

G. F. Claringbull and Max H. Hey
Department of Mineralogy, British Museum (Natural History)

Summary: Most of the pale yellow to deep brown gemstones previously supposed to be iron-rich olivine2 are a new mineral, sinhalite, having the ideal formula MgAlBO4. Of 22 brown and yellow stones examined 20 are sinhalite and the remaining two are close to common green olivine. Sinhalite is readily distinguishable from green olivine by its higher refractive indices and specific gravity and its much smaller optic axial angle.

Mineralogical Magazine; June 1952 v. 29; no. 217; p. 841-849; DOI: 10.1180/minmag.1952.029.217.01
© 1952, The Mineralogical Society
Mineralogical Society (