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Chemical Formula | CuSO4 · 5H2O |
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Composition | Hydrous copper sulfate |
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Color | Bright blue, sky-blue, greenish-blue |
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Streak | White |
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Hardness | 2½ |
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Crystal Forms and Aggregates |
(Triclinic) Crystals are short prismatic and thick tabular, but are extremely rare. Most commonly occurs as botryoidal or stalactitic masses and as fibrous veins, but also occurs encrusting, massive, as tiny, slender needles, and lenticular. |
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Transparency | Translucent |
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Specific Gravity | 2.3 |
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Luster | Vitreous, silky, dull |
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Cleavage | Indiscernible |
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Fracture | Conchoidal to splintery |
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Tenacity | Brittle, thin projections slightly flexible |
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Other ID Marks | 1) Has a sweetish, metallic taste --
Chalcanthite is poisonous -- Be careful when
testing 2) Slowly dissolves in water turning the water blue |
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Other Names |  Blue Vitriol, Copper
Vitriol, Copper sulfate |
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In Group | Sulfates ; Hydrous sulfates |
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All About | Chalcanthite is a secondary copper mineral formed through the oxidation of copper sulfides. It exists only in arid regions and dry
caves which are protected from moisture. It commonly
forms stalactitic and botryoidal growths on the walls and ceiling of mine
tunnels from oxidation of copper sulfides. Chalcanthite specimens must be kept away from water and moist conditions, for a chemical effect with water causes them to eventually crumble or dissolve. Most specimens are very fragile, and much care should be taken when handling them. Natural Chalcanthite crystals are extremely rare in nature. Well-shaped crystals are easily grown synthetically from copper sulfate solutions. If an exquisite crystal is for sale, it is almost surely not natural. Many unscrupulous mineral dealers sell large, synthetic Chalcanthite specimens without indicating that they are not natural. (Chalcanthite crystals are easily grown synthetically by obtaining a readily available chemical salt called copper sulfate, dissolving it in water, and letting the water evaporate. This will leave a crystallized mass of Chalcanthite behind.) Chalcanthite has a characteristic sweetish metallic taste, but taste testing is not recommended, as this mineral is poisonous. |
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Uses | Chalcanthite is an ore of copper in areas where it occurs in relative abundance, such as in Chile and Spain. Specimens are popular among collectors, and the synthetically grown crystals are commonly sold to unwary collectors. |
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Striking Features | Color and taste |
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Complex Tests | Gives off water when heated |
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Popularity (1-4) | 2 |
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Prevalence (1-3) | 2 |
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Demand (1-3) | 2 |
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Distinguishing Similar Minerals |
Melanterite - greener color |
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Commonly Occurs With |
Brochantite, Malachite, Calcite, Aragonite, Chalcopyrite |
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Noteworthy Localities |
In Chuquicamata and El Teniente in Chile,
large, fibrous masses occur in abundance and are mined as
an ore of copper. A sizable deposit also exists in
Minas de Riotinto, Spain. In the U.S., it found in many areas in the southwest, including Bingham Canyon, Salt Lake Co., Utah; Imlay, Pershing Co., Nevada; Ely, White Pine Co., Nevada; Bisbee, Cochise Co., Arizona; Ajo and Tiger, Pinal Co., Arizona; Globe, Gila Co., Arizona; Morenci, Greenlee Co., Arizona; and the Monitor-Mogul district, Alpine Co., California. It is also found in a dry cave in Ducktown, Polk Co., Tennessee. |
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Picture Icon Links |
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Picture Links | Sorry. No Images currently available. |
