THE MINERAL LIROCONITE

• Chemistry: Cu2Al(AsO4)(OH)4 - 4H2O , Hydrated Copper Aluminum Arsenate Hydroxide.
• Class: Phosphates
• Subclass: Arsenates
• Uses: Only as mineral specimens.
• Specimens

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Liroconite is a beautiful mineral that is not often available from any new sources. Fine crystal clusters were mined from the famous mines of Cornwall and Devon, England; the only site to produce significant specimens. But now that source is all but dried up although some of the old dumps have produced some specimens. Liroconite is found at other locations but only as traces. Collectors are almost completely relying on old collections to supply this mineral. Liroconite is a truly beautiful mineral with a typical bright blue color, a nice glassy luster and an interesting crystal habit. It forms from the oxidation of primary copper ores.

PHYSICAL CHARACTERISTICS:

• Color is typically blue to bluish green.
• Luster is vitreous.
• Transparency: Crystals are transparent to translucent.
• Crystal System is monoclinic; 2/m
• Crystal Habits include crusts with wedge to lens shaped crystals. Individual crystals can appear as if apart of the more symmetrical eight faced tetragonal bipyramid; but are actually composed of the faces of a four faced prism and four faces of two monoclinic domes.
• Cleavage is poor in two directions parallel to the prism faces.
• Fracture is uneven to conchoidal.
• Hardness is 2 - 2.5.
• Specific Gravity is approximately 2.95 - 3.00 (average for translucent minerals).
• Streak is pale blue.
• Other Characteristics: There is no reaction to acid as is true with azurite.
• Associated Minerals are clinoclase, azurite, malachite, caledonite and linarite and other oxidation zone copper ore minerals.
• Notable Occurrences include the famous mines of Cornwall and Devon, England such as the Wheal Gorland Mine; Russia; Germany; Cerro Gordo Mine, Inyo Co., California, USA and occasionally elsewhere.
• Best Field Indicators are crystal habit, color, low density, non reaction to acids, associations and streak.