Canasite is a mineral whose name is derived from its chemical composition of calcium (Ca), sodium (Na), and silicon (Si). It was approved in 1959 by

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Properties

It is a relatively rare mineral. It occurs as aggregates in

charoite Charoite ( ) is a rare silicate mineral with the chemical composition , first described in 1978. It is named after the Chara River, despite its being away from the discovery place.Ian Frazier, ''Travels in Siberia'', Farrar, Straus and Giroux, ...

, creating cabochons when contrasted against swirling purple charoite. It is extremely rare for canasite to be faceted. As crystals, it occurs in a size up to 10 cms, but in platy aggregates it can reach up to 20 cms in size. It is also granular. Twinning is usual, and can occur as

polysynthetic In linguistic typology, polysynthetic languages, formerly holophrastic languages, are highly synthetic languages, i.e., languages in which words are composed of many morphemes (word parts that have independent meaning but may or may not be able t ...

, which is when multiple twins align in a parallel. It has a barely detectable 1.12% potassium radioactivity based on the GRapi unit (

Gamma Ray American Petroleum Institute Units Gamma (; uppercase , lowercase ; ) is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop . In Modern Greek, this letter normally repr ...

). It consists of mostly oxygen (41.98%), silicon (26.8%) and calcium (15.93%), but otherwise contains sodium (7.31%), potassium (6.22%), which gives its

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

properties, fluorine (1.51%) and hydrogen (0.24%). There are two varieties of canasite: fluorcanasite and

frankamenite Frankamenite is the fluorine-dominate variation of the rare mineral canasite with a general formula of K3Na3Ca5(Si12O30) ,(OH)sub>4·(H2O). Frankamenite belongs to the triclinic crystal system, with the bases of its structure containing Ca-Na m ...

. Purple canasite may be confused with

stichtite Stichtite is a mineral, a Carbonate mineral, carbonate of chromium and magnesium; formula Mg6Cr2carbon, Coxygen, O3(Ohydrogen, H)16·4water, H2O. Its colour ranges from pink through lilac to a rich purple colour. It is formed as an alteration pro ...

, but recent research has found that the mineral advertized as canasite is a new specimen.

Occurrences and localities

Canasite has been found in three localities, all in Russia. In Khibiny massif, it grows in a differentiated alkalic massif in pegmatites, and in the Murun massif, it grows in charoitic rocks. It also occurs in the Kola Peninsula. In Khibiny massif, it is associated with

titanite Titanite, or sphene (), is a calcium titanium nesosilicate mineral, Ca Ti Si O5. Trace impurities of iron and aluminium are typically present. Also commonly present are rare earth metals including cerium and yttrium; calcium may be partly rep ...

eudialyte Eudialyte, whose name derives from the Greek phrase , , meaning "well decomposable", is a somewhat rare, nine-member-ring cyclosilicate mineral, which forms in alkaline igneous rocks, such as nepheline syenites. Its name alludes to its ready so ...

orthoclase Orthoclase, or orthoclase feldspar ( endmember formula K Al Si3 O8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture", because its two cleavage planes are at right angles ...

nepheline Nepheline, also called nephelite (), is a rock-forming mineral in the feldspathoid groupa silica-undersaturated aluminosilicate, Na3 K Al4 Si4 O16, that occurs in intrusive and volcanic rocks with low silica, and in their associated pegmatit ...

pyroxene The pyroxenes (commonly abbreviated Px) are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents ions of calcium (Ca), sodium (Na), iron ( ...

, lamprophyllite and fenaksite, while the specimens from Murun massif are usually associated with

tinaksite Tinaksite (chemical formula ) is a mineral found in northern Russia. Tinaksite can be grayish-white, yellowish, orange, or brown, and it is often found in charoite. Its name is derived from its composition: titanium (Ti), sodium (Na) potassium ( ...

and miserite.

References

{{reflist Minerals