Khomyakovite


Khomyakovite is an exceedingly rare mineral of the eudialyte group, with formula Na12Sr3Ca6Fe3Zr3WSi22O32. The original formula was extended to show the presence of both the cyclic silicate groups and M4-site silicon, according to the nomenclature of the eudialyte group. Some niobium substitutes for tungsten in khomyakovite. Khomyakovite is an iron-analogue of manganokhomyakovite, the second mineral being a bit more common. The two minerals are the only group representatives, beside taseqite, with species-defining strontium, although many other members display strontium diadochy. Khomyakovite is the third eudialyte-group mineral with essential tungsten.

Occurrence and association

Khomyakovite, manganokhomyakovite, johnsenite- and oneillite are four eudialyte-group minerals with type locality in Mont Saint-Hilaire, Quebec, Canada. Khomyakovite itself is associated with analcime, annite, natrolite, titanite, calcite, and pyrite.