Pectolite

Pectolite is a white to gray mineral, sodium calcium hydroxide inosilicate. It crystallizes in the triclinic system typically occurring in radiated or fibrous crystalline masses. It has a Mohs hardness of 4.5 to 5 and a specific gravity of 2.7 to 2.9. The gemstone variety, larimar, is a pale to sky blue.

Pectolite was first described in 1828 at Mt. Baldo, Trento Province, Italy. It named from the Greek pektos – “compacted” and lithos – “stone”.

It occurs as a primary mineral in nepheline syenites, within hydrothermal cavities in basalts and diabase and in serpentinites in association with zeolites, datolite, prehnite, calcite and serpentine.