Fluorite and Amethyst

ID	655
Mineral	Fluorite Amethyst
Location	Touissit - Jerada - Morocco
Fluorescence	LW-UV: close SW-UV: close
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Mindat data

ID	1576
Long ID	1:1:1576:5
Formula	`CaF₂`
IMA Status	APPROVED GRANDFATHERED
Description	Fluorite is found as a common gangue mineral in hydrothermal veins, especially those containing lead and zinc minerals. It is also found in some greisens, granites, pegmatites and high-temperature veins, and as a component of some marbles and other met...
Other Occurrences	Hydrothermal veins; cavities in sedimentary rocks; as a cementing material in sandstones; as hot springs deposits.
Industrial	Flux in steel making; source of fluorine
Discovery Year	1529
Diapheny	Transparent
Cleavage	Perfect on {111}, very easy.
Tenacity	brittle
Colour	Fluorite displays a wide variety of colour including (but not exclusively): purple, lilac, golden-yellow, green, colourless, blue, pink, champagne, brown, red and black.
Hardness (min)	4.0
Hardness (max)	4.0
Luminescence	Fluorescent, Short UV=blue, Long UV=blue.
Lustre	Vitreous
About the name	Named in 1797 by Carlo Antonio Galeani Napione from the Latin, fluere = "to flow" (for its use as a flux). The term fluorescence is derived from fluorite, which will often markedly exhibit this effect. The element fluorine also derives its name from fluorite, a major source of the element.
Streak	White
Crystal System	Isometric
Cleavage Type	Perfect
Fracture type	Splintery,Sub-Conchoidal
Morphology	Fluorite has seven main crystal forms: the most common Are the cube {100}, octahedron {111} and dodecahedron {110}; these forms having fixed Miller indices); and the tetrahexahedron {hk0}, trapezohedron {h11}, trisoctahedron {hhl} and hexoctahedron {hkl} (less common to quite rare crystal forms, having variable Miller indices). Combinations of two or more of these forms are common. The cuboctahedron (combined cube and octahedron) is less common than the combination of a cube and a docecahedron, the cubododecahedron. The faces of some crystal forms are more easily etched by nature than other faces, although this also depends on other parameters, and so none of the forms will always be smooth. Not all crystal faces will always be present, and sometimes certain faces are more developed than others, even within the same crystal form. Consequently, elongated crystals of fluorite have been observed. Crystals distorted at times by unequal development of faces, as of {013}. Often markedly composite; minute cubes aggregated to form an octahedron at times or as an overgrowth of crystals upon the corners of an earlier formed crystal of differing habit. Massive; compact; earthy, columnar (rare), or in globular aggregates; botryoidal (rare). For the Goldschmidt images we currently show the following habits with the crystallographic forms denoted here: no. 1 : a cube {100} no. 2 : an octahedron {111} no. 3 : a dodecahedron {110} no. 12: a cube {100}, modified by a hexoctahedron {421} no. 45: a cube {100}, highly modified by a dodecahedron {110}, two tetrahexahedrons: {210} and {310}, and a trapezohedron {211} no. 66: an octahedron {111}, modified by a dodecahedron {110} and a trisoctahedron {221}
Twinning	On {111}, usually as interpenetrating cubes (e.g., Strzegom, Poland), but also as contact spinel twins (e.g. Naica, Mexico and Chumar Bakhoor, Pakistan).
UV	Blue under LW-UV, due to Eu²⁺; other colors caused by different activators (white & cream - organic matter). Red (Mapimi, Mexico), pink (Doña Ana claims, AZ), white (Sterling Hill, NJ). Green response points to ytterbium (Siddike et al. 2003). May also be phosphorescent.
Thermal Behaviour	Melting point 1360°C.
Comment Luster	Dull when massive
shortcode_ima	Flr

ID	198
Long ID	1:1:198:0
Variety of	3337
Entry type	2
Other Occurrences	Very common, in many different environments. The commercially most important occurrences are in volcanic rocks, where amethyst crystals outline former gas cavities. In low and medium temperature hydrothermal veins associated with iron ores. As late overgrowth ("scepter quartz") on quartz in pegmatite and alpine-type environments.
Colour	Violet - purple
Lustre	Vitreous
About the name	From Greek "a-methystos", meaning "not drunk". In ancient times, it was believed that amethyst warded off drunkenness. Drinking cups were sometimes carved from amethyst. At the same time, the colour of the red wine drunk from these cups is said to have been approximately the same colour as the cups. Therefore, the wine could be diluted with water without the drinker noticing, thinking it was the material of the cup itself that warded off drunkenness.

Price: € 185

Dimensions: None mm x None mm x None mm

Weight: Not registered

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Symbol	Element
Ca	Calcium
F	Fluorine
O	Oxygen
Si	Silicium

Fluorite and Amethyst

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