Mineral Factbook

Paragonite

NaAl2(Si3Al)O10(OH)2IMA symbol: Pgapproved

Paragonite is a silicate mineral with the formula NaAl2(Si3Al)O10(OH)2. It has a Mohs hardness of 2.5-3, typically white, gray, green or yellow in color, with a pearly luster, a specific gravity of 2.78-2.9. Its streak is white.

Photos

Paragonite specimen photo
HolDu · CC BY-SA 3.0 de · Commons
Paragonite specimen photo
Kaethe17 · CC BY-SA 4.0 · Commons
Paragonite specimen photo
Dguendel · CC BY-SA 4.0 · Commons
Paragonite specimen photo
Géry PARENT · CC BY-SA 3.0 · Commons

Crystallography

Space groupC 1 2/c 1
Cell (Å, °)a = 5.128, b = 8.898, c = 19.287; α = 90, β = 94.35, γ = 90
Cell volume877.51 ų, Z = 4
Axial ratios0.5763:1:2.1676calculated from COD 9000905
Source structureCOD 9000905 (American Mineralogist, 1984) — 1 of 9 structures

Powder X-ray diffraction (calculated)

2θ (degrees, Cu Kα1)I/I₀ (max 100)
d (Å)4.3843.2052.539.6163.1572.91
I/I₀10091.685.681.158.358

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9000905; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)2.892 g/cm³calculated from COD 9000905
Hardness (Mohs)
2.5-3single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity
2.78-2.9 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892)
Color
gray, green, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892)
Streak
whitesingle sourceWikidata (CC0)
Luster
pearlysingle sourceDana, System of Mineralogy, 6th ed. (1892)

Chemistry (calculated)

Molecular weight382.2 g/molcalculated from the IMA formula
Composition (wt%)Na 6.02%, Al 21.18%, Si 22.05%, O 50.23%, H 0.53%

Classification

Nickel-Strunz (10th)9.EC.15Wikidata (CC0)
Nickel-Strunz (9th)9.EC.15Wikidata (CC0)