Armstrongite

CaZr(Si₆O₁₅)·₂H₂OIMA symbol: Asgapproved

Armstrongite is a silicate mineral with the formula CaZr(Si6O15)·2H2O, crystallizing in the monoclinic system. It has a calculated density of 2.616 g/cm3.

Photos

Armstrongite specimen photo — David Hospital · CC BY-SA 4.0 · Commons

Crystallography

Crystal system	monoclinic crystal systemWikidata (CC0)
Space group	C 1 2/m 1
Cell (Å, °)	a = 14.0178, b = 14.1289, c = 7.8366; α = 90, β = 109.436, γ = 90
Cell volume	1463.64 Å³, Z = 4
Axial ratios	0.9921:1:0.5547calculated from COD 9017088
Source structure	COD 9017088 (American Mineralogist, 2014) — 1 of 3 structures

Powder X-ray diffraction (calculated)

d (Å)	3.047	4.271	6.609	3.81	7.064	4.583
I/I₀	100	85	78	69.6	44.6	33.4

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9017088; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)	2.616 g/cm³calculated from COD 9017088

Chemistry (calculated)

Molecular weight	575.84 g/molcalculated from the IMA formula
Composition (wt%)	Ca 6.96%, Zr 15.84%, Si 29.26%, O 47.23%, H 0.7%

Classification

Nickel-Strunz (10th)	9.EA.35Wikidata (CC0)
Nickel-Strunz (9th)	9.EA.35Wikidata (CC0)
Dana (8th)	72.5.4.1Wikidata (CC0)