Prior to the investigations of Derby and Lee, this ore was considered identical with baddeleyite. It has now been shown, however, that it is a mechanical mixture of three minerals; namely, brazilite, zircon, and a new and unnamed zirconium silicate carrying about 75 per cent. zirconium oxide. This new mineral has the same crystal form as zircon (67 per cent. ZrO₂) but is readily soluble in hydrofluoric acid, while zircon is not affected, this being a characteristic differential test. The finely powdered mineral, on being treated with a weak solution of hydrofluoric acid, leaves a residue of minute, perfect, pyramidal crystals of zircon, the brazilite and new zirconium silicate going into solution. Several large outcrops of the ore occur on the extreme westerly edge of the plateau, one or two isolated boulders weighing as much as thirty tons. This very cursory examination of the zirconia deposits makes it unsafe to venture any conjecture as to the quantity of ore available. Suffice it to say, however, that the deposits have been traced for a distance of fifteen miles between Gascata and Caldas, and if surface indications are of any significance, are of vast extent. The oxides have also been found in the State of _Montana_, and in _Ceylon_, _Sweden_, and _Italy_, but none of these occurrences are of commercial importance. =The Silicate.=--The simple silicate, zircon, is found in seashore and river concentrations of monazite sands, associated with ilmenite, garnet, rutile, and various other heavy minerals usually found in such places. An important concentration of zircon occurs along the coast of _Brazil_, in the states of Bahia, Espirito Santo, and Rio de Janeiro, where cusps of the beaches are protected on the north by granite headlands and bordered by Tertiary bluffs, which are cut by various streams and lagoons that constantly furnish fresh material for the concentrating action of the tides and waves. Probably the next most important occurrence of zircon is in _India_, in the beach sands of the province or state of Travancore at the extreme southwestern end of the Hindustan peninsula. Next in importance is an occurrence in the _United States_ at Pablo Beach, Florida, where not only the beach sands, but the dunes bordering them, contain appreciable quantities of the following minerals in their relative order of abundance: ilmenite, garnet, epidote, zircon, rutile, and other heavy minerals including monazite.[101] [101] HESS, FRANK L., Letter of May 1, 1918.