Grossular Mineral Data

Grossular Mineral Data +

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General Grossular Information

Chemical Formula:

Ca3Al2(SiO4)3

Composition:

Molecular Weight = 450.45 gm

Calcium 26.69 % Ca 37.35 % CaO

Aluminum 11.98 % Al 22.64 % Al₂O₃

Silicon 18.71 % Si 40.02 % SiO₂

Oxygen 42.62 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₃Al₂(SiO₄)₃

Environment:

Contact metasomatic deposits.

IMA Status:

Valid Species (Pre-IMA) 1811

Locality:

Isle of Mull, Scotland. Link to MinDat.org Location Data.

Name Origin:

Grossular is from the Latin grossularia meaning "gooseberry." Hessonite is from the Greek hesson, meaning "slight" in reference to the smaller specific gravity.

Synonym:

Grossularite

Hessonite - brownish orange

ICSD 24944

PDF 39-368

Tsavorite - emerald green

Grossular Image

Images:

Grossular Diopside

Comments: Pale blue prismatic crystal of diopside with orange-brown grossular.
Location: Val d'Aosta, Italy. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Images:

Grossular

Comments: Gemmy, transparent, cinnamon-colored grossular crystals averaging 7 mm in size.
Location: Jeffrey mine, Asbestos, Quebec, Canada. Scale: 3.5 x 4 x 1.5 cm.
© Dan Weinrich

Images:

Grossular Vesuvianite

Comments: Blocky, tan-colored vesuvianite with white grossular (garnet).
Location: Sierra de la Cruz, Lago Jaco, Coahuila, Mexico. Scale: 3.5 x 4.5 cm.
© Fabre Minerals

Grossular Crystallography

Cell Dimensions:

a = 11.851, Z = 8; V = 1,664.43 Den(Calc)= 3.59

Crystal System:

Isometric - HexoctahedralH-M Symbol (4/m 3 2/m) Space Group: I a3d

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

By Intensity(I/I_o): 2.65(1), 1.58(0.9), 2.96(0.8),

Forms:

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Forms: [ 2 1 1]

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Crystal Structure:

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Novak G A , Gibbs G V , American Mineralogist , 56 (1971) p.791-825, The crystal chemistry of the silicate garnets, sample Mn-Gr

View Additional jPOWD Structure files for Grossular
[1] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [2] [20] [21] [22] [23] [24] [25] [26] [27] [28] [3] [4] [5] [6] [7] [8] [9]

Physical Properties of Grossular

Cleavage:

[???] Distinct

Color:

Brown, Colorless, Green, Gray, Yellow.

Density:

3.42 - 3.72, Average = 3.57

Diaphaniety:

Transparent to subtranslucent

Fracture:

Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.

Habit:

Crystalline - Fine - Occurs as well-formed fine sized crystals.

Habit:

Euhedral Crystals - Occurs as well-formed crystals showing good external form.

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Hardness:

6.5-7.5

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Resinous

Streak:

brownish white

Optical Properties of Grossular

Gladstone-Dale:

CI meas= 0.003 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.009 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2067,KPDmeas= 0.2078,KC= 0.2085

Optical Data:

Isotropic, n=1.734-1.75.

Calculated Properties of Grossular

Electron Density:

r_electron=3.55 gm/cc
note: r_Grossular=3.57 gm/cc.

Fermion Index

Fermion Index = 0.0093
Boson Index = 0.9907

Photoelectric:

PE_Grossular= 4.35 barns/electron
U=PE_Grossular x r_electron= 15.44 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Grossular is Not Radioactive

Grossular Classification

Dana Class:

51.4.3b.2 (51)Nesosilicate Insular SiO4 Groups Only

(51.4)with cations in [6] and >[6] coordination

(51.4.3b)Garnet group (Ugrandite series)

51.4.3b.1 Andradite Ca3Fe2(SiO4)3 I a3d 4/m 3 2/m

51.4.3b.2 Grossular Ca3Al2(SiO4)3 I a3d 4/m 3 2/m

51.4.3b.3 Uvarovite Ca3Cr2(SiO4)3 I a3d 4/m 3 2/m

51.4.3b.4 Goldmanite Ca3(V,Al,Fe)2(SiO4)3 I a3d 4/m 3 2/m

51.4.3b.5 Yamatoite? (Mn,Ca)3(V,Al)2(SiO4)3 I a3d 4/m 3 2/m

Strunz Class:

VIII/A.08-70 VIII - Silicates

VIII/A - Nesosilicates with [SiO4]4-groups, cations of octahedral and cubic orientation [8+6]

VIII/A.08 - Garnet group, Pyrope - Henritermierite

VIII/A.08-10 Pyrope Mg3Al2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-20 Almandine Fe3Al2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-30 Spessartine Mn3Al2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-40 Calderite (Mn,Ca)3(Fe,Al)2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-50 Knorringite Mg3Cr2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-60 Majorite Mg3(Fe,Al,Si)2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-70 Grossular Ca3Al2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-80 Hibschite Ca3Al2(SiO4)3-x(OH)4x(x=0.2-1.5) I a3d 4/m 3 2/m

VIII/A.08-90 Katoite Ca3Al2(SiO4)3-x(OH)4xx=1.5-3 I a3d 4/m 3 2/m

VIII/A.08-100 Hydrougrandite? (Ca,Mg,Fe)3(Fe,Al)2(SiO4)3-x(OH)4x I a3d 4/m 3 2/m

VIII/A.08-110 Andradite Ca3Fe2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-120 Schorlomite Ca3(Ti,Fe,Al)2[(Si,Fe,Fe)O4]3 I a3d 4/m 3 2/m

VIII/A.08-125 Morimotoite Ca3TiFeSi3O12 I a3d 4/m 3 2/m

VIII/A.08-130 Uvarovite Ca3Cr2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-138 Yamatoite! (Mn,Ca)3(V,Al)2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-140 Goldmanite Ca3(V,Al,Fe)2(SiO4)3 I a3d 4/m 3 2/m

VIII/A.08-150 Kimzeyite Ca3(Zr,Ti)2(Si,Al,Fe)3O12 I a3d 4/m 3 2/m

VIII/A.08-160 Henritermierite Ca3(Mn,Al)2(SiO4)2(OH)4 I 4₁/acd 4/m 2/m 2/m

Other Grossular Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

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Grossular

Ca3Al2(SiO4)3
Dana No: 51.4.3b.2 Strunz No: VIII/A.08-70
Locality:

Notes: