Mineral Factbook

Pectolite

NaCa2Si3O8(OH)IMA symbol: Pctgrandfathered

Pectolite is a silicate mineral with the formula NaCa2Si3O8(OH), crystallizing in the triclinic system. It has a Mohs hardness of 5, typically gray in color, with a silky or vitreous luster, a specific gravity of 2.68-2.78. Cleavage is perfect.

Photos

Pectolite specimen photo
Internet Archive Book Images · No restrictions · Commons
Pectolite specimen photo
Tõnis Saadre · CC BY-SA 4.0 · Commons
Pectolite specimen photo
Tõnis Saadre · CC BY-SA 4.0 · Commons
Pectolite specimen photo
Kaneva, E., Radomskaya, T., Suvorova, L., Sterkhova, I., and Mitichkin, M. · CC BY 4.0 · Commons

Crystallography

Crystal systemtriclinic crystal systemWikidata (CC0)
Space groupC -1
Cell (Å, °)a = 10.059, b = 10.88, c = 6.978; α = 98.84, β = 100.58, γ = 82.64
Cell volume737.853 ų, Z = 4
Axial ratios0.9245:1:0.6414calculated from COD 9000612
Source structureCOD 9000612 (American Mineralogist, 1978) — 1 of 2 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)2.8742.8823.0483.2463.2291.744
I/I₀1009456.646.630.130

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9000612; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)3.086 g/cm³calculated from COD 9000612
Hardness (Mohs)
5single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity
2.68-2.78 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892)
Color
graysingle sourceDana, System of Mineralogy, 6th ed. (1892)
Luster
silky, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892)
Cleavage
perfectDana, System of Mineralogy, 6th ed. (1892)

Chemistry (calculated)

Molecular weight332.4 g/molcalculated from the IMA formula
Composition (wt%)Na 6.92%, Ca 24.11%, Si 25.35%, O 43.32%, H 0.3%

Classification

Nickel-Strunz (10th)9.DG.05Wikidata (CC0)
Nickel-Strunz (9th)9.DG.05Wikidata (CC0)