Mooreite

minerals

torreyite

fluoborite

Formula: Mg15(SO4)2(OH)26.8H2O
Hydrated sulphate containing hydroxyl
Crystal System: Monoclinic
Specific gravity: 2.47 measured, 2.54 calculated
Hardness: 3
Streak: White to colourless
Colour: Colourless, light tan; colourless in transmitted light
Solubility: Soluble in acids
Environments

Metamorphic environments
Hydrothermal environments

Mooreite is a rare secondary mineral.

Localities

The type locality is the Sterling Mine, Ogdensburg, Franklin Mining District, Sussex County, New Jersey, USA. Here mooreite occurs rarely in cavities and veinlets in franklinitewillemitecalcite ore from a metamorphosed stratiform zinc orebody, in intimate association with altered pyrochroite, rhodochrosite and zincite. Cavities in the pyrochroite are lined, and some of the crevices are filled, with crystals of mooreite, which in turn may be covered by fluoborite (AM 14.165-172, AM 34.589-595). Other associated minerals include torreyite, franklinite, willemite and calcite (HOM, Dana).

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