Pectolite is a white to gray mineral, NaCa2Si3O8(OH), a sodium calcium hydroxide inosilicate.

It crystallizes in the triclinic system typically occurring in radiated or fibrous crystalline masses.

A highly sought-after variety known as larimar, is a pale to sky blue.

It was first described in 1828 at Mount Baldo, Trento Province, Italy, and named from the Greek pektos – "compacted" and lithos – "stone".

[3][4] 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.