Kassite (mineral)

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Kassite
Kassite, Cafetite, Lizardite-529446.jpg
Light yellow kassite's spherules with orange-yellow tabular cafetite in lizardite matrix. Base 2 mm. Locality: Val di Serra Quarry, Pilcante, Ala, Lagarina Valley, Trento Province, Trentino-Alto Adige (Trentino-Südtirol), Italy
General
CategoryHydroxide mineral
Formula
(repeating unit)
CaTi2O4(OH)2
Strunz classification 4.DH.10
Dana classification08.03.09
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Space group P21/a
Identification
Formula mass 235.09 g/mol
ColorBrown red, colorless, light yellow
Crystal habit Pseudo hexagonal
Twinning
Common, on {101} and {181}.
Cleavage {010} Perfect, {101} Indistinct
Fracture Brittle
Tenacity Very brittle
Mohs scale hardness5
Luster Adamantine
Streak White
Specific gravity 3.42
Density 3.42
Optical propertiesBiaxial (–), 2V=58°, dispersion very strong, r > v
Refractive index nα = 1.95, nβ = 2.13, nγ = 2.21
Birefringence δ = 0.26
Pleochroism none
Other characteristicsNot radioactive
References [1] [2]

Kassite is a rare mineral whose chemical formula is CaTi2O4(OH)2. It crystallizes in the orthorhombic crystal system and forms radiating rosettes and pseudo-hexagonal tabular crystals which are commonly twinned. Kassite crystals are brownish pink to pale yellow in color, are translucent, and have an adamantine luster. Cleavage is distinctly visible, and the crystals are very brittle.

It was first described in 1965 in the Afrikanda pyroxenite massif, a formation on Russia's Kola Peninsula and was named for Nikolai Grigorievich Kassin (1885–1949), a prominent Russian geologist. It occurs as miarolytic cavity fillings of alkalic pegmatites in the Kola occurrence and in nepheline syenite in the Magnet Cove igneous complex of Arkansas, US. Its mineral association includes cafetite (which with it is also polymorphous), perovskite, titanite, rutile and ilmenite.

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Natrolite

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Eudialyte

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Arfvedsonite

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Nenadkevichite

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Lorenzenite

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Cafetite

Cafetite is a rare titanium oxide mineral with formula (Ca,Mg)(Fe,Al)
2
Ti
4
O
12
·4(H
2
O)
. It is named for its composition, Ca-Fe-Ti.

Aliettite

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).

Loparite-(Ce)

Loparite-(Ce) is a granular, brittle oxide mineral of the perovskite class. It is black to dark grey and may appear grey to white in reflected light on polished thin section with reddish brown internal reflections. It has the chemical formula of (Ce,Na,Ca)(Ti,Nb)O3. Nioboloparite is a variation of Loparite-(Ce) containing niobium.

Perovskite Oxide mineral

Perovskite (pronunciation: ) is a calcium titanium oxide mineral composed of calcium titanate (CaTiO3). Its name is also applied to the class of compounds which have the same type of crystal structure as CaTiO3 (XIIA2+VIB4+X2−3), known as the perovskite structure. Many different cations can be embedded in this structure, allowing the development of diverse engineered materials.

Altisite is an exceedingly rare alkaline titanium aluminosilicate chloride mineral with formula Na3K6Ti2Al2Si8O26Cl3, from alkaline pegmatites. It is named after its composition (ALuminium, TItanium, and SIlicon).

Eveslogite is a complex inosilicate mineral with a chemical formula (Ca,K,Na,Sr,Ba)
48
[(Ti,Nb,Fe,Mn)
12
(OH)
12
Si
48
O
144
](F,OH,Cl)
14
found on Mt. Eveslogchorr in Khibiny Mountains, on the Kola peninsula, Russia. It was named after the place it was found. This silicate mineral occurs as an anchimonomineral veinlet that cross-cuts poikilitic nepheline syenite. This mineral appears to resemble yuksporite, as it forms similar placated fine fibrous of approximately 0.05 to 0.005mm that aggregates outwardly. The color of eveslogite is yellow or rather light brown. In addition, it is a semitransparent mineral that has a white streak and a vitreous luster. Its crystal system is monoclinic and possesses a hardness (Mohs) of 5. This newly discovered mineral belongs to the astrophyllite group of minerals and contains structures that are composed of titanosilicate layers. Limited information about this mineral exists due to the few research studies carried out since its recent discovery.

Kovdorskite

Kovdorskite, Mg2PO4(OH)·3H2O, is a rare, hydrated, magnesium phosphate mineral. It was first described by Kapustin et al., and is found only in the Kovdor Massif near Kovdor, Kola Peninsula, Russia. It is associated with collinsite, magnesite, dolomite, hydrotalcite, apatite, magnetite, and forsterite.

Ekplexite is a unique sulfide-hydroxide niobium-rich mineral with the formula (Nb,Mo)S
2
•(Mg
1-x
Al
x
)(OH)
2+x
. It is unique because niobium is usually found in oxide or, eventually, silicate minerals. Ekplexite is a case in which chalcophile behaviour of niobium is shown, which means niobium present in a sulfide mineral. The unique combination of elements in ekplexite has to do with its name, which comes from a Greek world on "surprise". The other example of chalcophile behaviour of niobium is edgarite, FeNb3S6, and both minerals were found in the same environment, which is a fenitic rock of Mt. Kaskasnyunchorr, Khibiny Massif, Kola Peninsula, Russia. Analysis of the same rock has revealed the presence of two analogues of ekplexite, kaskasite (molybdenum-analogue) and manganokaskasite (molybdenum- and manganese-analogue). All three minerals belong to the valleriite group, and crystallize in the trigonal system with similar possible space groups.

Cattiite is a phosphate mineral. The mineral was first found in a veins of dolomite carbonatites veins at the bottom of the Zhelezny (Iron) Mine in the Kovdor massif, Kola Peninsula, Russia. Cattiite was tentatively identified as Mg3(PO4)2 • 22H2O, which as a high hydrate magnesium orthophosphate. Later structural studies, revealed the existence of two polytypes named Mg3(PO4)2 • 22H2O-1A1 and Mg3(PO4)2 • 22H2O-1A2. 

References