Beryl (silicate of alumina and glucina), a mineral which scarcely differs except in colour from Emerald (q.v.), never exhibiting the bright rich green which characterises that gem, but colourless, yellowish, greenish-yellow or blue. The finer varieties, which are transparent and of beautiful colour, are distinguished as Precious Beryl, and are sometimes called Aquamarine.
These occur in crystals similar in form to those of emerald; but their regular hexagonal prism is more frequently modified by truncation on the angles or edges, acuminated, &c. The prisms are often long. Their sides are longitudinally striated, often deeply so; but the truncating or terminating planes are smooth. The coarser varieties of beryl (Common Beryl) are also found crystallised, but often massive. Beryl occurs chiefly in veins that traverse granite or gneiss, or imbedded in granite; sometimes it is found in alluvial soils formed from such rocks. Common beryl is found in a number of places in Europe. The mountains of Aberdeenshire, and those of Mourne in Ireland, yield precious beryl, which is also found in various parts of the United States, Brazil, Ceylon, and Siberia. It is somewhat less valuable than the emerald. For its use as a magic crystal, in which the future becomes visible, see Rossetti's Rose Mary.