pectolite
noun
pec·to·lite
ˈpektəˌlīt
plural -s
: a whitish or grayish monoclinic mineral NaCa2Si3O8(OH) consisting of a basic sodium calcium silicate occurring in crystal aggregates or fibrous masses (hardness 5, specific gravity 2.68–2.78)
Word History
Etymology
German pektolith, from Greek pēktos compacted (from pēgnynai to fix, fasten) + German -lith -lite