Dims: 4.0 x 2.2 x 2.2" (10.2 x 5.6 x 5.6 cm)
Wt: 11.9 oz. (338.0 g)
White Monster Mine, Inyo County, California, U.S.A.
Hundreds of Colemanite blades coat part of the beige host rock of this hand specimen. However, only a few dozen exceed 0.1" (3 mm) in length, so I will concentrate on them. These larger crystals acheive lengths of up to 0.8" (2.0 cm), and though a few of them are visibly damaged and broken, most are in excellent condition. Their monoclinic bladed form is also very good- all have well-defined edges and clean faces that possess a pearly luster. Their coloration is their most unusual trait, as all are colorless and slightly cloudy at their bases, but clear up and turn a pale brown color towards their terminations (see the second image). The host rock on which they rest is made up mostly of dirty, compact granules of Colemanite, but there seems to be a small amount of clay or siltstone present, too.