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Chemical Formula | Na2Ca(SO4)2 | ||
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Composition | Sodium calcium sulfate | ||
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Color | Colorless, cream, yellow, gray, light brown | ||
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Streak | White | ||
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Hardness | 2½ - 3 | ||
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Crystal Forms and Aggregates |
(Monoclinic) Occurs in characteristic,
unmistakable, well-formed, steep bipyramidal crystals. Crystals are sometimes striated, they may have rounded edges, and they
occasionally dissolve internally, leaving hollow crystal
shells. Glauberite also occurs encrusting and in compact crystal aggregates. |
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Transparency | Transparent to translucent | ||
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Specific Gravity | 2.7 - 2.8 | ||
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Luster | Greasy, vitreous, or dull | ||
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Cleavage | 1,1 - basal | ||
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Fracture | Conchoidal | ||
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Tenacity | Brittle | ||
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Other ID Marks | 1) Has a mild taste like salt 2) Slowly dissolves in water |
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In Group | Sulfates ; Hydrous sulfates | ||
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All About | Glauberite is now a rare mineral, but was
once more prevalent. This is evident by an abundance of
empty casts and pseudomorphs found in localities where little
or no Glauberite currently exists. Glauberite crystals
may internally dissolve, leaving hollow
"pockets" in the crystal. Glauberite forms in evaporite and clay deposits These environments enable a crystal to grow without interference from attached matter, so crystals can be perfect on all sides. Such crystals are known as "floating crystals". Glauberite does not keep well in collections for it is efflorescent, developing white powder on its surface which dulls its luster. To avoid this, specimens should be placed in conditions where this effect is minimal, such as a damp area. |
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Uses | Glauberite is used for the extraction of Glauber's salt. It is popular among mineral collectors specializing in crystals, due to its unusual form of crystals. | ||
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Striking Features | Crystal habits and taste | ||
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Complex Tests | Soluble in hydrochloric acid | ||
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Popularity (1-4) | 2 | ||
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Prevalence (1-3) | 3 | ||
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Demand (1-3) | 1 | ||
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Distinguishing Similar Minerals |
Glauberite's crystal form and occurrences distinguish it from all minerals. | ||
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Commonly Occurs With |
Halite, Anhydrite, Thenardite | ||
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Noteworthy Localities |
Glauberite is found in Europe in Salzburg,
Austria; Strassfurt, Germany; Vallarubia, Spain; and
Lorraine, France. Glauberite is also found in South
America in the Atacama Desert of Chile. In the U.S., the most famous occurrence is Camp Verde, Yavapai Co., Arizona. Most specimens in collections are from this locality. Glauberite also occurs in several dry lake deposits in Southern California, such as Searles Lake, San Bernardino Co., and the Saline Valley, Inyo Co. Perfectly shaped empty crystal casts exist in sandstone in Paterson, Passaic Co., New Jersey, but only few intact crystals were obtained from there. Many minerals were also found in thzt locality as pseudomorphs after Glauberite. |
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Picture Icon Links |
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Picture Links | 1. Twinned Glauberite crystals |
