Big piece of Agate from Minas Gerais, Brazil. The piece is slightly unpolished in the upper left corner.
If was found in one of the only fair trade quarries in Minas Gerais. Since we highly support ethical products, we prefer to have this piece. Next to the ethical value, it has a nice deep and dark color.
Minas Gerais is a state in Brazil and its name translated into English means General Mines. Many of the localities and photos here on Mindat are for specimens that have come from several rather distinct geological settings in the state. Probably the best known of these are the pegmatite minerals like tourmaline, beryl, quartz etc that come from the pegmatites in the north west granitic region of the state and whose center, business wise if not geologically is the town of Governador Valadares.
Another prolific producer of specimens are the quartz specimens that come from the sandstone formations in the northwest part of Minas Gerais. Their sale and distribution is centered in the town of Corinto, but there are many little towns in the sandstone region of the state that have quartz producing localities near them. Though there are many varieties of quartz from these sandstone deposits, they are usually sufficiently different from those produced by the granite pegmatites to the east that it is not hard to tell them apart. In this area is also the old colonial town of Diamantina that for perhaps 200 years was the center of diamond and gold production in Brazil.
In the southern part of the state is a big iron mining region that has produced some spectacular crystal specimens of hematite and countless tons off massive lapidary grade hematite. Though it would be possible for some of the mines to still produce lapidary grade hematite they don’t want to sell in quantities of less than trains of 100 carloads of hematite. In Ouro Preto (black gold), the old colonial town where the School of Mines is located can be found dealers selling specimens of Imperial Topaz from deposits of that mineral near the town. Also near by is the famous gold mine at Nova Lima that is well known to collectors for its find specimens of siderite, pink apatite and other minerals. All in all the state is well named.