Zirconium (Named From The Mineral Zircon), a rare metal, recognized as a peculiar substance by Klaproth in 1789, and first separated by Berzelius in 1824. It is a component of the minerals zircon, hyacinth, eudialyte, polymignite, oerstedite, fergusonite, and catapleiite. The double fluoride of potassium and zirconium being heated with potassium, and the residue when cold treated with dilute hydrochloric acid, the amorphous zirconium falls as a black powder. It is purified by washing with chloride of ammonium, and then with alcohol. Under the burnisher it takes a slight metallic lustre, and its conducting power for electricity is very low. Crystallized zirconium was prepared by Troost in 18G5 by heating 1 part of the double fluoride of potassium and zirconium with 1½ part of aluminum in a plumbago crucible to the point of fusion of iron. After the operation the aluminum is found to be covered with crystalline laminae, which maybe separated by dissolving the aluminum in hydrochloric acid. Thus obtained, zirconium is very hard, and resembles antimony in color, lustre, and brittleness. It is readily dissolved in nitromuriatic and hydrofluoric acid; other acids have little effect. Its specific gravity is 4.15, symbol Zr, and atomic weight 89.6. There is one oxide, Zr02, which acts both as a base and as an acid.
Its hydrate gelatinizes, and dissolves readily in acids. The salts of zirconia have an astringent taste; they are precipitated by the caustic alkalies, and not redissolved in excess of these. Infusion of galls gives a yellow precipitate with them, phosphate of soda a white one. The mineral zircon ranks among precious stones, its varieties in appearance being brown, red, yellow, gray, white, adamantine, and translucent. A variety of zircon, called jargon, exhibits in its natural state and when fused with borax a remarkable spectrum, which was supposed by Sorby to indicate the presence of a new element, for which he proposed the name of jargonium. Subsequent research convinced him that the lines in the spectrum were due to the presence of uranic oxide, whence he concludes that the supposed jargonium has no existence. Zirconia has been employed as a substitute for lime or magnesia in oxyhydrogen illumination. It is very refractory, and possesses great radiating power. To avoid expense, only the tip of the cylinder is made of zirconia.