ADELITE

CaMg(AsO₄)(OH)
Orthorhombic

Adelite was reported from Franklin by Dunn (1979c) and subsequently verified from Sterling Hill where it was locally abundant.

Description

Adelite from Franklin occurs in crystals of undetermined habit and as colorless aggregates; adelite from Sterling Hill is massive. The color of adelite varies from medium yellow to white at Franklin and pinkish brown to brown at Sterling Hill. No physical or optical data exist, and there is no discernible fluorescence in ultraviolet. It is best verified using X-ray methods.

Composition

Adelite is a calcium magnesium arsenate hydroxide mineral. Analyzed local material contains much Zn in solid solution towards austinite (Table 25), but contains little Mn and only traces of Fe. Sterling Hill material has very similar composition.

Occurrence and paragenesis

At Franklin, adelite is rare. In this initial occurrence, adelite occurs as 5 mm, yellow, euhedral crystals in hodgkinsonite, with barite, allactite, rhodochrosite, and franklinite, on franklinite-willemite  gneissic ore. It was also found as white, 1 mm, rounded hemispherules with a granular-aggregate texture, within chlorophoenicite which appeared to have replaced zincite.

At Sterling Hill, adelite was found in moderate abundance in the 1220 pillar on the 800 level, associated with alleghanyite, kraisslite, sphalerite, rhodochrosite, willemite, and franklinite. It was also found with johnbaumite/svabite, zincite, barite, and calcite on the 1200 level.

Copyright © 1995 by Pete J. Dunn			Website by Herb Yeates
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This page created: January 11, 2001