Sanidine Mineral Data

Sanidine Mineral Data +

General Sanidine Information

Chemical Formula:

(K,Na)(Si,Al)4O8

Composition:

Molecular Weight = 274.30 gm

Potassium 10.69 % K 12.88 % K₂O

Sodium 2.10 % Na 2.82 % Na₂O

Aluminum 9.84 % Al 18.59 % Al₂O₃

Silicon 30.72 % Si 65.71 % SiO₂

Oxygen 46.66 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K_0.75Na_0.25AlSi₃O₈

Environment:

Acid volcanic rocks.

IMA Status:

Valid Species (Pre-IMA) 1808

Locality:

Common world wide occurrences. Link to MinDat.org Location Data.

Name Origin:

From the Greek sanis - "little plate" and idos - "to see."

Sanidine Image

Images:

Sanidine

Comments: Blocky, opalescent crystal of sanidine.
Location: Mina La Pili, Carmago, Chihuahua, Mexico. Scale: Crystal size 3x2 cm.
© Dave Barthelmy

Sanidine Crystallography

Axial Ratios:

a:b:c =0.6588:1:0.5534

Cell Dimensions:

a = 8.562, b = 12.996, c = 7.193, Z = 4; beta = 116.016° V = 719.28 Den(Calc)= 2.53

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): 3.26(1), 3.22(0.9), 3.27(0.75),

Forms:

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Forms: [ 1 1 0] [ 1 0 1] [ 0 0 1] [ 0 1 0]

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Crystal Structure:

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Phillips M W , Ribbe P H , American Mineralogist , 58 (1973) p.263-270, The structures of monoclinic potassium-rich feldspars

View Additional jPOWD Structure files for Sanidine
[1] [10] [11] [12] [2] [3] [4] [5] [6] [7] [8] [9]

Physical Properties of Sanidine

Cleavage:

[001] Perfect, [010] Good

Color:

Colorless, White, Gray, Yellowish white, Reddish white.

Density:

2.52

Diaphaniety:

Transparent to translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Blocky - Crystal shape tends to be equant (e.g. feldspars).

Habit:

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

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

6 - Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Pearly

Streak:

white

Optical Properties of Sanidine

Gladstone-Dale:

CI meas= -0.013 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.009 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2076,KPDmeas= 0.2085,KC= 0.2058

Optical Data:

Biaxial (-), a=1.518-1.525, b=1.523-1.53, g=1.525-1.531, bire=0.0060-0.0070, 2V(Calc)=48-64, 2V(Meas)=60-0. Dispersion r < v distinct.

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Pleochroism (z):

colorless.

Calculated Properties of Sanidine

Electron Density:

r_electron=2.51 gm/cc
note: r_Sanidine=2.53 gm/cc.

Fermion Index

Fermion Index = 0.01458
Boson Index = 0.98542

Photoelectric:

PE_Sanidine= 2.57 barns/electron
U=PE_Sanidine x r_electron= 6.44 barns/cc.

Radioactivity:

GRapi = 152.94 (Gamma Ray American Petroleum Institute Units)

Estimated Radioactivity from Sanidine - barely detectable

Sanidine Classification

Dana Class:

76.1.1.2 (76)Tectosilicate Al-Si Framework

(76.1)with Al-Si frameworks

(76.1.1)K (Na,Ba) feldspars

76.1.1.1 Orthoclase KAlSi3O8 C 2/m 2/m

76.1.1.2 Sanidine (K,Na)(Si,Al)4O8 C 2/m 2/m

76.1.1.3 Hyalophane (K,Ba)Al(Si,Al)3O8 C 2/m 2/m

76.1.1.4 Celsian BaAl2Si2O8 I21/c 2/m

76.1.1.5 Microcline KAlSi3O8 C1 1

76.1.1.6 Anorthoclase (Na,K)AlSi3O8 C1 1

76.1.1.7 Rubicline! (Rb,K)AlSi3O8 P1 1

76.1.1.8 Filatovite! K[(Al,Zn)2(As,Si)2O8] I2/c 2/m

Strunz Class:

VIII/J.06-20 VIII - Silicates

VIII/J - Tectosilicates (network) without anions unfamiliar to the tetraheders

VIII/J.06 - Feldspar group, Buddingtonite - Orthoclase - Slawsonite series

VIII/J.06-10 Buddingtonite (NH4)AlSi3O8·0.5(H2O) P 2₁ or P 2₁/m Mono

VIII/J.06-15 Kokchetavite! KAlSi3O8 P 6/mmm(?) 6/m 2/m 2/m

VIII/J.06-20 Sanidine (K,Na)(Si,Al)4O8 C 2/m 2/m

VIII/J.06-30 Microcline KAlSi3O8 C1 1

VIII/J.06-35 Rubicline! (Rb,K)AlSi3O8 P1 1

VIII/J.06-40 Orthoclase KAlSi3O8 C 2/m 2/m

VIII/J.06-50 Hyalophane (K,Ba)Al(Si,Al)3O8 C 2/m 2/m

VIII/J.06-60 Celsian BaAl2Si2O8 I21/c 2/m

VIII/J.06-70 Paracelsian BaAl2Si2O8 P 2₁/c 2/m

VIII/J.06-80 Slawsonite (Sr,Ca)Al2Si2O8 P 2₁/a 2/m

Other Sanidine Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

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Sanidine

(K,Na)(Si,Al)4O8
Dana No: 76.1.1.2 Strunz No: VIII/J.06-20
Locality:

Notes: