BERYLLONITE  , a

mineral phosphate of beryllium and sodium, NaBePO4, found as highly complex orthorhombic crystals and as broken fragments in the disintegrated material of a granitic vein at Stoneham, Maine, where it is associated with felspar, smoky quartz, beryl and columbite . It was discovered by Prof . E . S . Dana in 1888, and named beryllonite because it contains beryllium in large amount . The crystals vary from colourless to white or pale yellowish, and are trans-parent with a vitreous lustre; there is a perfect cleavage in one direction . Hardness 51-6; specific gravity 2.845 . A few crystals have been cut and faceted, but, as the refractive index is no higher than that of quartz, they do not make very brilliant gem-stones .