BRAZIL • Santa Terezinha

In the center of Goias, near the mining community of Campos Verdes

Finds: Discovered accidentally in April 1981; production of emerald rough rose from 35 kg in 1981 to 52 tons in 1988; present production is insignificant

Beryl: Colored green by chromium (0,05 to 1.54%), iron (0.48 to 1.82%) and vanadium (0.06 to 0.08%); highest chromium and iron contents of any Brazilian emerald; often sharply zoned with colorless core and green outer zone; rarities are cat's eye stones up to 6 carat

Geo: Stratabound mineralization in fold structures along the plane of a long the plane of foliation in tale schists of the Precambrian voleanosedimentary series of the Santa Terezinha within greenschist facies metamorphic overprint; the Santa Terezinha emerald deposit is 522 million years old

Mat: Tale schist, phlogopite schist, tremolite phlogopite tale chloritecarbonate schist and quartz-carbonate lenses, quartzite

Sim: Porangatu, Fazenda das Lajes (Itaberai) and Pela Ema-Minacu

Incl: Carbonates, sulphides, tale, phlogopite, quartz, feldspars, amphiboles, epidote, gamet, rutile, spinels, hematite and ilmenite

Ref: Biondi (1990); Giuliani et al (1990,1997)



Abbreviations:
Sim: Similar or other deposits; Finds: Quality of Emerald specimens and significant finds; Beryl: Type of beryl or Emerald and the chromophorous elements;Geo: Geology and origin; Mat: Matrix or host rock; Incl: Solid inclusion (fluid inclusions are not noted); Ref: References or recommended reading for further information on a deposit

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