Glucina

Glucina, GlO, the one oxide formed by glucinum, is an earth obtained by Vauquelin in 1797 from the emerald, and which was afterwards found in the beryl and a few minerals. Glucina is a white, loosely coherent powder, without taste or smell. When heated to the strongest temperature of a wind furnace it assumes the form of microscopical prisms resembling corundum. Glucina is perfectly insoluble in water, and only dissolves in dilute acids when it has not been ignited strongly. It is easily soluble in boiling concentrated sulphuric acid, and if fused with an alkali, and the cold mass treated with water, the glucina goes into solution. Glucinum hydroxide, Gl(OH)₂, is thrown down as a gelatinous precipitate when a glucinum salt is precipitated with ammonia. Glucinum forms salts with the various acids; they are colourless, and much resemble those of aluminium. The mineral phenakite is a pure silicate of glucina. The beryl, of which the emerald is a variety, is a double silicate of glucina and alumina. The mineral euclase is also a double silicate of the same earths; while the chrysoberyl is an aluminate of glucina, coloured with ferric oxide.