Adelite is a calcium magnesium arsenate hydroxide mineral. Analyzed local material contains much Zn in solid solution towards austinite, but contains little Mn and only traces of Fe. Sterling Hill material has very similar composition.
Adelite was reported from Franklin by Dunn (1979c) and subsequently verified from Sterling Hill where it was locally abundant.
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.
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. (Dunn, 1995)

 Location Found: Franklin and Ogdensburg
 Year Discovered: 1884
 Formula: CaMg(AsO4)(OH)
 Essential Elements: Arsenic, Calcium, Hydrogen, Magnesium, Oxygen
 All Elements in Formula: Arsenic, Calcium, Hydrogen, Magnesium, Oxygen
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered" 1891
 To find out more about this mineral at minDat's website, follow this link   Adelite

Dunn, Pete J. (1995). Franklin and Sterling Hill New Jersey: the world's most magnificent mineral deposits. Franklin, NJ.: The Franklin-Ogdensburg Mineralogical Society. p.655

The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 20, No. 2 - September 1979, pg. 4Contributions to the Mineralogy of Franklin and Sterling Hill New Jersey, Adelite (small article)
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