| 词条 | Pectolite |
| 释义 |
| name = Pectolite | category = Inosilicate mineral | image = Pectolite-263712.jpg | imagesize = 260px | caption = | formula = NaCa2Si3O8(OH) | molweight = | strunz = | dana = | system = Triclinic | class = Pinacoidal ({{overline|1}}) (same H-M symbol) | symmetry = P{{overline|1}} | unit cell = a = 7.99 Å, b = 7.03 Å, c = 7.03 Å; α = 90.51°, β = 95.21°, γ = 102.53°; Z = 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 = | diaphaneity = Translucent to opaque | gravity = 2.84 - 2.90 | density = | polish = | opticalprop = Biaxial (+) | refractive = nα = 1.594 - 1.610 nβ = 1.603 - 1.614 nγ = 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 = [1][2][3] }} Pectolite is a white to gray mineral, NaCa2Si3O8(OH), 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. OccurrenceIt was first described in 1828 at Mt. Baldo, Trento Province, Italy and named from the Greek pektos – "compacted" and lithos – "stone".[2][3] 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
References1. ^Handbook of Mineralogy 2. ^1 Mindat w/ localities 3. ^1 Webmineral External links
6 : Sodium minerals|Calcium minerals|Inosilicates|Gemstones|Triclinic minerals|Luminescent minerals |
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