Crossite Mineral Data

General Crossite Information

Chemical Formula:

Na2(Mg,Fe++)3(Al,Fe+++)2Si8O22(OH)2

Composition:

Molecular Weight = 795.32 gm

Sodium 5.78 % Na 7.79 % Na₂O

Magnesium 6.11 % Mg 10.14 % MgO

Aluminum 2.54 % Al 4.81 % Al₂O₃

Iron 8.78 % Fe 9.03 % FeO / 2.51 % Fe₂O₃

Silicon 28.25 % Si 60.44 % SiO₂

Hydrogen 0.25 % H 2.27 % H₂O

Oxygen 48.28 % O

______ ______

100.00 % 96.98 % = TOTAL OXIDE

Empirical Formula:

Na₂Mg₂Fe²⁺Al_0.75Fe³⁺_0.25(Si₈O₂₂)(OH)₂

Environment:

High pressure, low temperature metamorphic mineral. Discredited by IMA amphibole subcommittee (now glaucophane or ferroglaucophane or magnesioriebeckite or riebeckite).

IMA Status:

Discredited IMA 1997 - Valid Species (Pre-IMA) 1894

Locality:

Berkeley, Conta Costa Co., USA. Link to MinDat.org Location Data.

Name Origin:

Named in 1894 for Charles Whitman Cross, (1854-1949), geologist, United States Geological Survey.

Synonym:

Discredited

ICSD 27459

PDF 20-376

Crossite Image

Images:

Crossite

Comments: Black prismatic crystal clusters of crossite.
Location: near Valley Ford, Sonoma County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Crossite

Comments: Long metallic, black, prismatic crystals or crossite on matrix.
Location: Webbing, Lammertal, Salzburg, Austria. Scale: Picture size 2.5 mm.
© Tom Loomis / Dakota Matrix

Crossite Crystallography

Axial Ratios:

a:b:c =0.5387:1:0.2969

Cell Dimensions:

a = 9.647, b = 17.905, c = 5.316, Z = 2; beta = 103.6° V = 892.48 Den(Calc)= 2.96

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 8.31(1), 3.08(0.7), 2.71(0.4),2.53(0.2), 3.4(0.2), 4.48(0.2), 4.87(0.2), 8.95(0.1),

Physical Properties of Crossite

Cleavage:

{110} Perfect, {010} Good

Color:

Blue, Gray, Gray blue.

Density:

3.16

Diaphaneity:

Transparent to translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Tabular - Form dimensions are thin in one direction.

Hardness:

6 - Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Crossite

Gladstone-Dale:

CI meas= -0.02 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.089 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2214,KPDmeas= 0.2074,KC= 0.2033
Ncalc = 1.6 - 1.64

Optical Data:

Biaxial (-), a=1.64-1.659, b=1.645-1.666, g=1.652-1.67, bire=0.0110-0.0120, 2V(Calc)=72-82, 2V(Meas)=12-65. Dispersion very strong, r > v.

Pleochroism (x):

wine yellow, pale yellow, colorless, or pale mauve blue.

Pleochroism (y):

blue, prussian blue, purplish blue, or deep blue.

Pleochroism (z):

grayish violet, violet, blue, or deep mauve blue.

Calculated Properties of Crossite

Electron Density:

Bulk Density (Electron Density)=3.13 gm/cc
note: Specific Gravity of Crossite =3.16 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Crossite= 3.98 barns/electron
U=PE_Crossite x rElectron Density= 12.48 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Crossite is Not Radioactive

Crossite Classification

Dana Class:

66.01.03c.03 (66)Inosilicate Double-Width Unbranched Chains, W=2

(66.01)with P=2 amphibole configuration

(66.01.03c)Group 4, the sodic amphiboles

66.01.03c.01 Glaucophane []Na2(Mg3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.02 Ferroglaucophane []Na2(Fe3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.03 Crossite? Na2(Mg,Fe)3(Al,Fe)2Si8O22(OH)2 C 2/m 2/m

66.01.03c.04 Magnesioriebeckite []Na2[(Mg,Fe)3Fe2]Si8O22(OH)2 C 2/m 2/m

66.01.03c.05 Riebeckite []Na2(Fe3Fe2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.06 Eckermannite NaNa2(Mg4Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.07 Ferro-eckermannite NaNa2(Fe4Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.08 Magnesio-arfvedsonite NaNa2(Mg4Fe)Si8O22(OH)2 C 2/m 2/m

66.01.03c.09 Arfvedsonite NaNa2(Fe4Fe)Si8O22(OH)2 C 2/m 2/m

66.01.03c.09a Fluoro-magnesio-arfvedsonite! NaNa2(Mg,Fe)4Fe[Si8O22](F,OH)2 C 2/m 2/m

66.01.03c.09b Potassicarfvedsonite! KNa2Fe4FeSi8O22(OH)2 C 2/m 2/m

66.01.03c.10 Kozulite NaNa2Mn4(Fe,Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.11 Nyboite NaNa2(Mg3Al2)Si7AlO22(OH)2 C 2/m 2/m

66.01.03c.11a Ferronyboite! NaNa2(Fe)3Al2(Si7Al)O22(OH)2 C 2/m 2/m

66.01.03c.11b Ferric-ferronyboite! NaNa2(Fe)3(Fe)2(Si7Al)O22(OH)2 C 2/m 2/m

66.01.03c.11c Fluoronyboite! NaNa2(Al2Mg3)(Si7Al)O22(F,OH)2 C 2/m 2/m

66.01.03c.12 Leakeite NaNa2(Mg2Fe2Li)Si8O22(OH)2 C 2/m 2/m

66.01.03c.12a Ferroleakeite! NaNa2(Fe)3(Fe)2Li(Si8O22)(OH)2 C 2/m 2/m

66.01.03c.12b Potassicleakeite! KNa2Mg2Fe2LiSi8O22(OH)2 C 2/m 2/m

66.01.03c.13 Kornite Na(CaNa)Fe4(Al,Fe)Si7AlO22(OH)2 C 2/m 2/m

66.01.03c.14 Ungarettiite NaNa2(Mn2Mn3)Si8O22O2 C 2/m 2/m

66.01.03c.15 Fluoro-ferroleakeite NaNa2(Fe2Fe2Li)Si8O22F2 C 2/m 2/m

66.01.03c.16 Obertiite! NaNa2(Mg3FeTi)Si8O22(O,F,OH)2 C 2/m 2/m

66.01.03c.17 Dellaventuraite! NaNa2(Mg2,Mn,Li,Ti)Si8O22O2 C 2/m 2/m

Strunz Class:

09.DE.25 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DE -Inosilicates with 2-periodic double chains, Si4O11; amphibole family

09.DE.25 Arfvedsonite NaNa2(Fe4Fe)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ferroglaucophane []Na2(Fe3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Crossite? Na2(Mg,Fe)3(Al,Fe)2Si8O22(OH)2 C 2/m 2/m

09.DE.25 Eckermannite NaNa2(Mg4Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Glaucophane []Na2(Mg3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Fluoro-ferroleakeite NaNa2(Fe2Fe2Li)Si8O22F2 C 2/m 2/m

09.DE.25 Ferro-eckermannite NaNa2(Fe4Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ferroleakeite! NaNa2(Fe)3(Fe)2Li(Si8O22)(OH)2 C 2/m 2/m

09.DE.25 Ferronyboite! NaNa2(Fe)3Al2(Si7Al)O22(OH)2 C 2/m 2/m

09.DE.25 Ferric-ferronyboite! NaNa2(Fe)3(Fe)2(Si7Al)O22(OH)2 C 2/m 2/m

09.DE.25 Obertiite! NaNa2(Mg3FeTi)Si8O22(O,F,OH)2 C 2/m 2/m

09.DE.25 Nyboite NaNa2(Mg3Al2)Si7AlO22(OH)2 C 2/m 2/m

09.DE.25 Magnesioriebeckite []Na2[(Mg,Fe)3Fe2]Si8O22(OH)2 C 2/m 2/m

09.DE.25 Kozulite NaNa2Mn4(Fe,Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Kornite Na(CaNa)Fe4(Al,Fe)Si7AlO22(OH)2 C 2/m 2/m

09.DE.25 Leakeite NaNa2(Mg2Fe2Li)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Magnesio-arfvedsonite NaNa2(Mg4Fe)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ungarettiite NaNa2(Mn2Mn3)Si8O22O2 C 2/m 2/m

09.DE.25 Riebeckite []Na2(Fe3Fe2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Potassicleakeite! KNa2Mg2Fe2LiSi8O22(OH)2 C 2/m 2/m

09.DE.25 Fluoronyboite! NaNa2(Al2Mg3)(Si7Al)O22(F,OH)2 C 2/m 2/m

09.DE.25 Fluoro-magnesio-arfvedsonite! NaNa2(Mg,Fe)4Fe[Si8O22](F,OH)2 C 2/m 2/m

09.DE.25 Potassicarfvedsonite! KNa2Fe4FeSi8O22(OH)2 C 2/m 2/m

09.DE.25 Dellaventuraite! NaNa2(Mg2,Mn,Li,Ti)Si8O22O2 C 2/m 2/m

Other Crossite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana)

See Also:

Links to other databases for Crossite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info

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Print or Cut-and-Paste your Crossite Specimen Label here :

Crossite

Na2(Mg,Fe++)3(Al,Fe+++)2Si8O22(OH)2
Dana No: 66.01.03c.03 Strunz No: 09.DE.25
Locality:

Notes: