Goyazite

minerals

montebrasite

crandallite

herderite

Formula: SrAl3(PO4)(PO3OH)(OH)6
Phosphate containing hydroxyl, crandallite group, forms series with crandallite and with gorceixite
Specific gravity: 3.26
Hardness: 4½ to 5
Streak: White
Colour: White, yellow, honey-yellow, pink, lilac, orange or colourless; colourless in transmitted light
Solubility: Slowly soluble in acids
Environments

Pegmatites
Carbonatites
Sedimentary environments
Hydrothermal environments

Goyazite occurs in granitic pegmatites, in hydrothermal argillic alteration zones, in kaolinitic claystones derived from air-fall volcanic tuff, in sedimentary phosphate deposits, in carbonatites and in detrital deposits, including diamantiferous sands (Mindat, HOM). Associated minerals include apatite, baryte, diamond, herderite, kaolinite, monazite, pyrite and quartz (Mindat).

Localities

The type locality is Diamantina, Minas Gerais, Brazil, as placer nodules (Mindat).

At the Alto Benedito pegmatite, Frei Martinho, Borborema mineral province, Paraíba, Brazil, goyazite is associated with herderite, apatite and quartz (HOM).

In the Simplon tunnel, Switzerland, goyazite occurs on anhydrite (Dana).

At the Wigu carbonatite, Tanzania, goyazite is associated with monazite, sphalerite, pyrite, baryte and quartz (HOM).

At the Belaya Kalitva region, Donetz basin, Ukraine, goyazite occurs in limestone with baryte, pyrite and quartz (Dana).

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, goyazite has been found as crystals to several mm, also schorl replaced by muscovite has been found with an overgrowth of goyazite and hydroxylherderite. A granular mixture of montebrasite and goyazite has been found. The Emmons pegmatite is an example of a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.508).

At the Chickering mine, Cheshire county, New Hampshire, USA, goyazite has been found in cavities adjacent to altered montebrasite, associated with quartz, albite and fluorapatite (R&M 90.5.417).

Common impurities: Ba,F

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