Eudialyte

Na₁₅Ca₆Fe₃Zr₃Si(Si₂₅O₇₃)(O,OH,H₂O)₃(Cl,OH)₂IMA symbol: Eudapproved

Eudialyte is a silicate mineral with the formula Na15Ca6Fe3Zr3Si(Si25O73)(O,OH,H2O)3(Cl,OH)2, crystallizing in the trigonal system. It has a Mohs hardness of 5-5.5, typically brown, red or rose in color, with a vitreous luster, a specific gravity of 2.91-2.93. Its streak is red.

Photos

Crystallography

Crystal system	trigonal crystal systemWikidata (CC0)
Space group	R -3 m :H
Cell (Å, °)	a = 14.2646, b = 14.2646, c = 30.186; α = 90, β = 90, γ = 120
Cell volume	5319.31 Å³, Z = 3
Axial ratios	1.0000:1:2.1161calculated from COD 9010544
Source structure	COD 9010544 (The Canadian Mineralogist, 1999) — 1 of 10 structures

Powder X-ray diffraction (calculated)

d (Å)	2.858	2.98	7.132	5.717	4.317	3.22
I/I₀	100	81.3	61.4	59.9	39	36.7

xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9010544; idealized occupancies, no preferred orientation.

Physical properties

Density (calculated)	2.881 g/cm³calculated from COD 9010544
Hardness (Mohs)	5-5.5single sourceDana, System of Mineralogy, 6th ed. (1892)
Specific gravity	2.91-2.93 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892)
Color	brown, red, rosesingle sourceDana, System of Mineralogy, 6th ed. (1892)
Streak	whitesingle sourceWikidata (CC0) redsingle sourceDana, System of Mineralogy, 6th ed. (1892)
Luster	vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892)

Classification

Nickel-Strunz (10th)	9.CO.10Wikidata (CC0)
Nickel-Strunz (9th)	9.CO.10Wikidata (CC0)