Pink “Optical” Calcite from Chihuahua / Mexico with 24 pieces (Rare)

Pink “Optical” Calcite from Chihuahua / Mexico with 24 pieces (Rare)

Blue Onyx (“Aragonite”) Pyramid-big from Patagonia / Argentina.

Blue Onyx (“Aragonite”) Pyramid-big from Patagonia / Argentina.

Mexico “El Classico” mineral sales box with 24 pieces (6 types each 4 pieces)

Beautiful colorful box with 6 types (Orange, Emerald & Blue Calcite) and new in the box the new finds Zebra, Dragon Blood Calcite together with Black Obsidian - total 24 pieces!
Availability: In stock
SKU
10490
  • Buy 3 for €59.00 each and save 14%
Mexico “El Classico” mineral sales box with 24 pieces (6 types each 4 pieces) is available to buy in increments of 1

The mineral calcite (also called calcite) consists mainly of the salt calcium carbonate (CaCO3) and is one of the most abundant minerals in the earth's crust. Calcium carbonate is formed when soluble calcium ions come into contact with CO2 (carbon dioxide forms a carbonate ion when there is a positive ion in a solution). Calcium carbonate is a sparingly soluble salt, causing the CaCO3 formed to precipitate; this goes according to the following reaction: Ca2 + (aq) + CO32- (aq) - → CaCO3 (s). Calcite has a Trigonal crystal system and belongs to the space group R-3c. A very pure form of calcite is also called weld splat because of the birefringence of light in this mineral. It has a rhomboid structure and is sometimes found as rhomboid prisms, but it often occurs in other forms, such as scalenoedra, or in fiber, grain, or compact form. The crystal structure is mainly a result of the temperature, degree of supersaturation in the vicinity of the crystal and the CO2 pressure. The calcite structure is the stable modification of CaCO3 at room temperature. There is another form, aragonite, which turns into calcite at 743K. In its pure crystalline form, calcite is clear, colorlessly translucent, but due to impurities (such as from copper or sodium salts) it can take on all kinds of colors, such as gray, blue, violet, green and even black. Often it is also opaque white. The mineral can exhibit both phosphorescence and fluorescence. The hardness is by definition 3. Calcite is highly birefringent. This optical property was first described by Rasmus Bartholin when the Icelandic form of the mineral, which consists of large, crystal-clear romboëders, became available. Christiaan Huygens gave the first explanation with his wave theory of light. Calcite is a common constituent of sedimentary rocks, veins and in deposits in hot springs and cavernous carving areas (as drip rock). It is the mineral that forms limestone and therefore the most abundant mineral of biological origin. Calcite is the main constituent of limestone, chalk rock and marble and it is also an important constituent of marl, calcareous sandstone and limestone shales. Calcite provides chemical weathering in igneous and metamorphic rocks, resulting in sedimentary rocks. Calcite is soluble under light pressure in water containing CO2. As it falls into the air, rainwater absorbs the gaseous carbon dioxide, making it acidic. This acidic rainwater is able to dissolve lime. In underground currents this material can transport in solution until, after contact with atmospheric pressure, CO2 escapes and the calcite precipitates. This is how stalagmites and stalactites are formed in caves.

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