It is said that the Hungarian Opals are less likely to deteriorate than any others. Still the danger of deterioration is not great in any Opal. The other important countries from which precious Opals are obtained are Mexico, Honduras and Australia. The Mexican Opals are mostly of the fire Opal variety. They are mined in a number of the States of the Republic—Queretaro, Hidalgo, Guerrero, Michoacan, Jalisco and San Luis Potosi. The oldest mines are in the State of Hidalgo, near Zimapan, where the Opal occurs in a red trachyte. Most of the Mexican Opals on the market at the present time, however, come from the State of Queretaro, where mining for them is conducted on a more extensive scale. The Opal here occurs in long veins in a porphyritic trachyte, and is mined at various points. The stones are cut and polished by workmen in the city of Queretaro who use ordinary grind-stones and chamois skins for the work and are said to receive an average wage of 23 cents a day. The Honduras Opals reach foreign markets but rarely and usually uncut. The mines are in the western part of Honduras, in the Department of Gracias. They are little worked, but there is no doubt that extensive deposits exist which might afford a good supply of gems if they were properly exploited. The Australian Opals come from several localities, the most prominent at the present time being White Cliffs, New South Wales. The matrix is a Cretaceous sandstone which has been permeated by hot volcanic waters. Shells, bones and other fossils are found here entirely altered to precious Opal, making objects of great beauty. In 1899 Opals to the value of $650,000 were sold from this single region. There is no doubt that the present popularity of the Opal is due to some extent to the supply of beautiful stones which has come from these mines at prices at from one-third to one-tenth those of the Hungarian stones. Other localities in Australia whence precious Opals are obtained are places on the Barcoo River and Bulla Creek, Queensland, and occasional finds in West Australia. No localities in the United States yielding precious Opals in any quantity have yet been discovered. Some good stones have been cut from an occurrence in Idaho, and some other minor finds have been made, but they possess little commercial importance at present.