Fraipontite | |
---|---|
General | |
Category | Phyllosilicate |
Formula (repeating unit) | (Zn,Al)3(Si,Al)2O5(OH)4 |
IMA symbol | Fpt [1] |
Strunz classification | 9.ED.15 |
Crystal system | Monoclinic |
Crystal class | Domatic (m) (same H-M symbol) |
Space group | Cm |
Unit cell | a = 5.34, b = 9.21 c = 14.12 [Å]; β = 93.2°; Z = 2 |
Identification | |
Color | Blueish, yellow white light green |
Crystal habit | Fibrous to porcelaneous massive |
Mohs scale hardness | 3.5 – 4 |
Luster | Silky |
Streak | White to pale green |
Diaphaneity | Opaque to translucent |
Specific gravity | 3.08 – 3.10 |
Optical properties | Biaxial (-) |
Refractive index | nα = 1.620 nβ = 1.624 nγ = 1.624 |
Birefringence | δ = 0.004 |
2V angle | Measured: 15° to 20° |
References | [2] [3] [4] |
Fraipontite is a zinc aluminium silicate mineral with a formula of (Zn,Al)3(Si,Al)2O5(OH)4. [2] [3]
It is a member of the kaolinite-serpentine mineral group and occurs as an oxidation product of zinc deposits. It occurs with smithsonite, gebhardite, willemite, cerussite and sauconite. [2]
It was first described in 1927 for an occurrence in Vieille Montagne, Verviers, Liège Province, Belgium. [3] It was named for Julien Jean Joseph Fraipont (1857–1910), and Charles de Fraipont, geologists of Liege, Belgium. [4] In addition to the type locality in Belgium, it has been reported from Tsumeb, Namibia; Laurium, Greece; Swaledale, North Yorkshire, England; the Silver Bill mine, Cochise County, Arizona, the Blanchard Mine, Socorro County, New Mexico and the Mohawk mine, San Bernardino County, California in the US; and from the Ojuela mine, Mapimi, Durango, Mexico. [2]
A synonym of the fraipontite is the zinalsite, which was reported in 1956 for an occurrence in Kazakhstan. [5] [6]
Hemimorphite is the chemical compound Zn4(Si2O7)(OH)2·H2O, a component of mineral calamine. It is a silicate mineral which, together with smithsonite (ZnCO3), has been historically mined from the upper parts of zinc and lead ores. Both compounds were originally believed to be the same mineral and classified as calamine. In the second half of the 18th century, it was discovered that these two different compounds were both present in calamine. They closely resemble one another.
Germanite is a rare copper iron germanium sulfide mineral, Cu26Fe4Ge4S32. It was first discovered in 1922, and named for its germanium content. It is only a minor source of this important semiconductor element, which is mainly derived from the processing of the zinc sulfide mineral sphalerite. Germanite contains gallium, zinc, molybdenum, arsenic, and vanadium as impurities.
Hydrozincite, also known as zinc bloom or marionite, is a white carbonate mineral consisting of Zn5(CO3)2(OH)6. It is usually found in massive rather than crystalline form.
Erythrite, also known as red cobalt, is a secondary hydrated cobalt arsenate mineral with the formula Co
3(AsO
4)
2•8H
2O. Erythrite and annabergite, chemical formula Ni
3(AsO
4)
2•8H
2O, or nickel arsenate form a complete series with the general formula (Co,Ni)
3(AsO
4)
2•8H
2O.
Wurtzite is a zinc and iron sulfide mineral with the chemical formula (Zn,Fe)S, a less frequently encountered structural polymorph form of sphalerite. The iron content is variable up to eight percent. It is trimorphous with matraite and sphalerite.
Adamite is a zinc arsenate hydroxide mineral, Zn2AsO4OH. It is a mineral that typically occurs in the oxidized or weathered zone above zinc ore occurrences. Pure adamite is colorless, but usually it possess yellow color due to Fe compounds admixture. Tints of green also occur and are connected with copper substitutions in the mineral structure. Olivenite is a copper arsenate that is isostructural with adamite and there is considerable substitution between zinc and copper resulting in an intermediate called cuproadamite. Zincolivenite is a recently discovered mineral being an intermediate mineral with formula CuZn(AsO4)(OH). Manganese, cobalt, and nickel also substitute in the structure. An analogous zinc phosphate, tarbuttite, is known.
Willemite is a zinc silicate mineral and a minor ore of zinc. It is highly fluorescent (green) under shortwave ultraviolet light. It occurs in a variety of colors in daylight, in fibrous masses and apple-green gemmy masses. Troostite is a variant in which part of the zinc is partly replaced by manganese, it occurs in solid brown masses.
Weissite is a telluride mineral, a copper telluride. Its chemical formula is Cu
2−xTe. Weissite has hexagonal crystal structure. Its specific gravity is 6 and its Mohs hardness is 3. Occurrence is in Gunnison County, Colorado, Arizona and New Mexico in the United States. It is also reported from Kalgoorlie, Western Australia and Dalarna and Värmland, Sweden.
Zincochromite is a zinc chromium oxide mineral with the formula ZnCr2O4. It is the zinc analogue of chromite, hence the name. It was first described in 1987 as an occurrence in a uranium deposit near Lake Onega, Russia. It has also been reported from Dolo Hill, New South Wales, Australia, and from the Tarkwa Mine in the Ashanti gold belt of Ghana.
Legrandite is a rare zinc arsenate mineral, Zn2(AsO4)(OH)·(H2O).
Clinohedrite is a rare silicate mineral. Its chemical composition is a hydrous calcium-zinc silicate; CaZn(SiO4)·H2O. It crystallizes in the monoclinic system and typically occurs as veinlets and fracture coatings. It is commonly colorless, white to pale amethyst in color. It has perfect cleavage and the crystalline habit has a brilliant luster. It has a Mohs hardness of 5.5 and a specific gravity of 3.28–3.33.
Aliettite is a complex phyllosilicate mineral of the smectite group with a formula of (Ca0.2Mg6(Si,Al)8O20(OH)4·4H2O) or [Mg3Si4O10(OH)2](Ca0.5,Na)0.33(Al,Mg,Fe2+)2−3(Si,Al)4O10(OH)2·n(H2O).
Ordoñezite or ordóñezite is a rare tetragonal zinc antimonate mineral with chemical formula: ZnSb2O6.
Spurrite is a white, yellow or light blue mineral with monoclinic crystals. Its chemical formula is Ca5(SiO4)2CO3.
Xocomecatlite is a rare tellurate mineral with formula: Cu3(TeO4)(OH)4. It is an orthorhombic mineral which occurs as aggregates or spherules of green needlelike crystals.
Chaidamuite is a rare zinc – iron sulfate mineral with chemical formula: ZnFe3+(SO4)2(OH)·4H2O.
Stillwellite-(Ce) is a rare-earth boro-silicate mineral with chemical formula (Ce,La,Ca)BSiO5.
Utahite is an extremely rare secondary copper zinc tellurate mineral found as a product of oxidation. Its chemical formula is Cu5Zn3(Te6+O4)4(OH)8·7H2O.
Hemihedrite is a rare lead zinc chromate silicate mineral with formula Pb10Zn(CrO4)6(SiO4)2(F,OH)2. It forms a series with the copper analogue iranite.
Xitieshanite is a hydrous iron sulfate–chloride mineral with chemical formula: Fe3+(SO4)Cl·6(H2O).
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