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."

Name Pronunciation:

Sanidine

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

Diaphaneity:

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
Ncalc = 1.52

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.

Calculated Properties of Sanidine

Electron Density:

Bulk Density (Electron Density)=2.51 gm/cc
note: Specific Gravity of Sanidine =2.53 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

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)
Concentration of Sanidine per GRapi unit = 0.65 (%)

Estimated Radioactivity from Sanidine - barely detectable

Sanidine Classification

Dana Class:

76.01.01.02 (76)Tectosilicate Al-Si Framework

(76.01)with Al-Si frameworks

(76.01.01)K (Na,Ba) feldspars

76.01.01.01 Orthoclase KAlSi3O8 C 2/m 2/m

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

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

76.01.01.04 Celsian BaAl2Si2O8 I21/c 2/m

76.01.01.05 Microcline KAlSi3O8 C1 1

76.01.01.06 Anorthoclase (Na,K)AlSi3O8 C1 1

76.01.01.07 Rubicline! (Rb,K)AlSi3O8 P1 1

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

Strunz Class:

09.FA.30 09 - SILICATES (Germanates)

09.F - Tektosilicates without Zeolitic H2O

09.FA -Tektosilicates without additional non-tetrahedral anions, (Al,B):Si = 1:1

09.FA.30 Buddingtonite (NH4)AlSi3O8•0.5(H2O) P 2₁ or P 2₁/m Mono

09.FA.30 Celsian BaAl2Si2O8 I21/c 2/m

09.FA.30 Anorthoclase (Na,K)AlSi3O8 C1 1

09.FA.30 Hyalophane (K,Ba)Al(Si,Al)3O8 C 2/m 2/m

09.FA.30 Orthoclase KAlSi3O8 C 2/m 2/m

09.FA.30 Microcline KAlSi3O8 C1 1

09.FA.30 Rubicline! (Rb,K)AlSi3O8 P1 1

09.FA.30 Sanidine (K,Na)(Si,Al)4O8 C 2/m 2/m

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

Sanidine

(K,Na)(Si,Al)4O8
Dana No: 76.01.01.02 Strunz No: 09.FA.30
Locality:

Notes: