Brazil is one of the most gem-rich countries in the world. Fine examples of nearly every gem mineral known has been mined from Brazil, particularly from the states of Minas Gerais and Bahia but in lesser quantities from Rio Grande do Norte, Rio Grande do Sul, Paraiba, Espirito Santo, and some other states. Gem beryls and tourmalines are especially well known from Brazil and they are available in nearly every color imaginable. Brazilian aquamarine from Medina, Minas Gerais are some of the finest and largest gem crystals in the world, for example. The Jonas Mine is another great example of Brazil’s gem wealth- it produced a room sized pocket of cranberry tourmaline worth millions of dollars.
Although gems cut from Brazilian rough can be of very high quality, many cut stones show evidence of treatment, particularly heat treating which can deepen color saturation or even change colors of certain gems like Topaz. This is an important factor to be aware of when purchasing stones from Brazil.
Many unusual minerals occur in Brazil. These species may have unusual composition, properties, color, or crystal habit. The following minerals and mineral varieties are examples of what makes Brazilian minerals unique: Bahianite is perhaps the most unusual mineral from Brazil. Discovered and found only from alluvial material found in rivers in Bahia State. The mineral itself is a caramel colored, resinous material that is composed of aluminum, antimony, oxygen, and hydrogen. It is abnormally hard- approximately as hard as corundum (sapphire or ruby) for unknown reasons.
Blue elbaite tourmaline rich in copper was first discovered in Brazil, and was named Paraiba tourmaline after the state it was discovered in. The highest quality Paraiba tourmaline comes from the Batalha Mine, which produces it in tiny softball sized pockets associated with mica, quartz, and feldspars. Often all of the minerals from the Batalha mine are flecked with tiny specs of native copper. Fine Paraiba tourmaline ranges in color from aqua-blue to purple and can be worth thousands per carat if of sufficient clarity and saturation.
Imperial topaz from Ouro Preto, Minas Gerais is of considerable curiosity because geologists do not know what the original environment where it formed was like. The gemmy orange, red, or purple topaz weathered by the intense tropical climate out of its original host rock and was transported by erosion processes to the present location where it is mined, which is from a cement-like limonite matrix.