{{Short description|Silicate mineral}} {{infobox mineral | name = Pectolite | category = Inosilicate mineral | image = Pectolite-263712.jpg | imagesize = 260px | caption = | formula = NaCa<sub>2</sub>Si<sub>3</sub>O<sub>8</sub>(OH) | IMAsymbol = Pct<ref>{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3 |pages=291–320|doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}</ref> | molweight = | strunz = | dana = | system = Triclinic | class = Pinacoidal ({{overline|1}}) <br/><small>(same H-M symbol)</small> | symmetry = ''P''{{overline|1}} | unit cell = a = 7.99&nbsp;Å, b = 7.03&nbsp;Å, <br/>c = 7.03&nbsp;Å; α = 90.51°, <br/>β = 95.21°, γ = 102.53°; Z&nbsp;=&nbsp;2 | color = Colorless, whitish, grayish, yellowish | colour = | habit = Tabular to acicular, radiating fibrous, spheroidal, or columnar; massive | twinning = Twin axis [010] with composition plane [100], common | cleavage = Perfect on {100} and {001} | fracture = Uneven | tenacity = Brittle; tough when compact | mohs = 4.5 – 5 | luster = Silky, subvitreous | streak = White | diaphaneity = Translucent to opaque | gravity = 2.84 – 2.90 | density = | polish = | opticalprop = Biaxial (+) | refractive = n<sub>α</sub> = 1.594 – 1.610 n<sub>β</sub> = 1.603 – 1.614 n<sub>γ</sub> = 1.631 – 1.642 | birefringence = δ = 0.037 | pleochroism = | 2V = Measured: 50° to 63°, Calculated: 42° to 60° | dispersion = r > v weak to very strong | extinction = | length fast/slow = | fluorescence= | other = | alteration = | references = <ref name=Handbook>[http://rruff.geo.arizona.edu/doclib/hom/pectolite.pdf Handbook of Mineralogy]</ref><ref name=Mindat>[http://www.mindat.org/show.php?id=3141&ld=1&pho= Mindat w/ localities]</ref><ref name=Webmin>[http://webmineral.com/data/Pectolite.shtml Webmineral]</ref> }} '''Pectolite''' is a white to gray mineral, NaCa<sub>2</sub>Si<sub>3</sub>O<sub>8</sub>(OH), a 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. A highly sought-after variety known as larimar, is a pale to sky blue. There is also a whitish form of the mineral from Alaska that is sometimes marketed as 'Alaska jade'.

==Occurrence== [[File:Larimar.jpg|thumb|left| Pectolite var. Larimar ]] It was first described in 1828 at Mount Baldo, Trento Province, Italy, and named from the Greek ''pektos'' – "compacted" and ''lithos'' – "stone".<ref name=Mindat/><ref name=Webmin/>

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. It is found in a wide variety of worldwide locations.

==See also== *Serandite – the manganese analogue

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== References == {{Reflist}}

==External links== *[https://web.archive.org/web/20050925004352/http://mineral.galleries.com/minerals/silicate/pectolit/pectolit.htm Mineral galleries] {{commons category|Pectolite}}

Category:Sodium minerals Category:Calcium minerals Category:Inosilicates Category:Gemstones Category:Triclinic minerals Category:Luminescent minerals Category:Minerals in space group 2

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