The gemstone deposits of Brazil: occurrences, production and

Vermelhão mine, Saramenha, Ouro Preto, Ouro Preto, Minas Gerais, Brazil

PDF) Brazilian Colored Gemstones in Portuguese 18th–19th Century Jewelry (Proceedings of the IV International Gemological Symposium)

PDF) Gemstones of Nigeria: An Overview of Their Geological Occurrence, Provenance and Origin

Les difficultés de la filière brésilienne face à la nouvelle organisation mondiale du négoce des pierres de couleur

Gemological map of the State of Piauí (Oliveira, 1998 – CPRM).

Amethyst Cluster 3.42 with Stand Brazilian Collectible Specimen, Includes Display Case - Mini Museum

Mineralatlas Lexikon

PDF) Brazilian Colored Gemstones in Historical Jewelry

Crystallographic and crystallochemical controls on oxygen isotope analysis of hematite by SIMS - ScienceDirect

Mineralatlas Lexikon