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Introducing the Mineral of the Month series

Introducing the Department of Geosciences "Mineral of the Month" series. On or around the 1st of every month, curator Christopher Holl will select a speciment from the department's mineral collection, write a brief description, and publish the record to our newsfeed.

We begin the series with the mineral:

Variscite

Mineral Name Variscite
Specimen Number 005
Record ID 6112
Locality Nickname Fairfield, Utah
State Utah
County Utah
Town Fairfield
Min Dat Locality Page  http://www.mindat.org/loc-4148.html
   
Online page http://ivyserver.princeton.edu/mineralcollection/detail.php?onlypic=0&id=6112&mineral=Variscite&keyword=
   
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http://ivyserver.princeton.edu/mineralcollection/index.php

   
About the Collection http://www.princeton.edu/geosciences/about/mineral-collection/

 

This is of the “crown jewels” of the Gem and Mineral collection, a large and very fine cut Variscite nodule from the Little Green Monster Mine in Clay Canyon, near Fairfield, Utah.  Arthur Montgomery (’31) worked the now-closed mine in the mid 1930s with his partner Ed Over, and several decades later generously donated this specimen to the collection.  These nodules were deposited as pure blue-green variscite (hydrous aluminum phosphate, AlPO4 · 2H2O) in brecciated limestone.  Later, colorful alteration products formed along fluid-containing cracks in the variscite.  Here we see yellow crandallite (hydrous calcium aluminum phosphate, CaAl3(PO4)2(OH)5 · H2O) and gray wardite (hydrous sodium aluminum phosphate, NaAl3(PO4)2(OH)4 · 2H2O).  There are likely other rare minerals in this specimen in smaller quantities.

Variscite