Cuspidine Mineral Data

General Cuspidine Information

Chemical Formula:

Ca4Si2O7(F,OH)2

Composition:

Molecular Weight = 365.48 gm

Calcium 43.86 % Ca 61.37 % CaO

Silicon 15.37 % Si 32.88 % SiO₂

Hydrogen 0.14 % H 1.23 % H₂O

Oxygen 32.83 % O

Fluorine 7.80 % F 7.80 % F

- % F -3.28 % -O=F₂

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₄Si₂O₇F_1.5(OH)_0.5

Environment:

Ejected masses from Mte. Somma, Vesuvius.

IMA Status:

Valid Species (Pre-IMA) 1876

Locality:

At Monte Somma and Vesuvius, Campania, and in the Alban Hills, as at Ariccia, Lazio, Italy. Link to MinDat.org Location Data.

Name Origin:

From the Greek cuspis, for a spear, the characteristic shape of the twinned crystals.

Synonym:

Custerite

ICSD 34339

PDF 41-1474

Cuspidine Image

Images:

Cuspidine

Comments: Tan spear-shaped micro crystals of cuspidine in diopside.
Location: San Vito Quarry, Vesuvius, Napoli, Campania, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Jasmundite Cuspidine

Comments: Tan-brownish crystals of jasmundite and dark green cuspidine with gehlenite and spinel in matrix.
Location: Bellerberg, Eifel, Germany. Scale: Not Given.
© Diederik Visser

Cuspidine Crystallography

Axial Ratios:

a:b:c =1.034:1:0.7161

Cell Dimensions:

a = 10.93, b = 10.57, c = 7.57, Z = 4; beta = 110.1° V = 821.30 Den(Calc)= 2.96

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 3.062(1), 2.943(0.35), 3.259(0.3),

Physical Properties of Cuspidine

Cleavage:

{001} Good, {110} Imperfect

Color:

Colorless, Green, White, Light pink.

Density:

2.8 - 2.9, Average = 2.84

Diaphaneity:

Transparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

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

Hardness:

5-6 - Between Apatite and Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Cuspidine

Gladstone-Dale:

CI meas= -0.019 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.019 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2012,KPDmeas= 0.2089,KC= 0.2051
Ncalc = 1.57 - 1.61

Optical Data:

Biaxial (+), a=1.586-1.592, b=1.595-1.596, g=1.598-1.606, bire=0.0120-0.0140, 2V(Calc)=58-66, 2V(Meas)=63. Dispersion r > v distinct.

Calculated Properties of Cuspidine

Electron Density:

Bulk Density (Electron Density)=2.95 gm/cc
note: Specific Gravity of Cuspidine =2.96 gm/cc.

Fermion Index:

Fermion Index = 0.0079273277
Boson Index = 0.9920726723

Photoelectric:

PE_Cuspidine= 6.02 barns/electron
U=PE_Cuspidine x rElectron Density= 17.74 barns/cc.

Radioactivity:

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

Cuspidine Classification

Dana Class:

56.02.04.03 (56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O

(56.02)with cations in [4] and/or >[4] coordination

(56.02.04)Cuspidine - Wohlerite group

56.02.04.01 Baghdadite Ca3(Zr,Ti)Si2O9 P 2₁/a 2/m

56.02.04.02 Burpalite Na2CaZrSi2O7F2 P 2₁/a 2/m

56.02.04.03 Cuspidine Ca4Si2O7(F,OH)2 P 2₁/c 2/m

56.02.04.04 Lavenite (Na,Ca)2(Mn,Fe)(Zr,Ti,Nb)Si2O7(O,OH,F) P 2₁/a 2/m

56.02.04.05 Wohlerite NaCa2(Zr,Nb)Si2O7(O,OH,F)2 P 2₁/m 2/m

56.02.04.06 Niocalite Ca14Nb2(Si2O7)4O6F2 Pa m

56.02.04.07 Hiortdahlite (Ca,Na,Y)3(Zr,Ti)Si2O7(F,O,OH)2 P1 1

56.02.04.08 Rosenbuschite (Ca,Na)3(Zr,Ti)Si2O8F P1 1

56.02.04.09 Hainite Na4Ca8(Ti,Zr,Mn,Fe)3Si8O28F8 P1 1

56.02.04.10 Janhaugite (Na,Ca)3(Mn,Fe)3(Ti,Zr,Nb)2Si4O15(OH,F,O)3 P 2₁/n 2/m

56.02.04.11 Jennite Ca9Si6O18(OH)6•8H2O P1 1

56.02.04.12 Komarovite (Ca,Mn)2(Nb,Ti)2Si2O7(O,F)2•3.5(H2O) Unk Ortho

56.02.04.13 Natrokomarovite* Na6CaNb6[Si4O12F2•4(H2O) C mmm 2/m 2/m 2/m

56.02.04.14 Suolunite Ca2Si2O5(OH)2•(H2O) F dd2 mm2

56.02.04.15 Mongolite Ca4Nb6Si5O24(OH)10•5(H2O) Unk Tetra

56.02.04.16 Kristiansenite! Ca2ScSn(Si2O7)(Si2O6OH) C1 1

56.02.04.17 Kochite! Na2(Na,Ca)4Ca4(Mn,Ca)2Zr2Ti2(Si2O7)4(O,F)4F4 P1 1

56.02.04.18 Marianoite! Na2Ca4(Nb,Zr)2(Si2O7)2(O,F)4 P 2₁ 2/m

Strunz Class:

09.BE.17 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BE -Si2O7 groups with additional anions;

09.BE.17 Baghdadite Ca3(Zr,Ti)Si2O9 P 2₁/a 2/m

09.BE.17 Janhaugite (Na,Ca)3(Mn,Fe)3(Ti,Zr,Nb)2Si4O15(OH,F,O)3 P 2₁/n 2/m

09.BE.17 Burpalite Na2CaZrSi2O7F2 P 2₁/a 2/m

09.BE.17 Cuspidine Ca4Si2O7(F,OH)2 P 2₁/c 2/m

09.BE.17 Hiortdahlite (Ca,Na,Y)3(Zr,Ti)Si2O7(F,O,OH)2 P1 1

09.BE.17 Lavenite (Na,Ca)2(Mn,Fe)(Zr,Ti,Nb)Si2O7(O,OH,F) P 2₁/a 2/m

09.BE.17 Niocalite Ca14Nb2(Si2O7)4O6F2 Pa m

09.BE.17 Normandite! NaCa(Mn,Fe)(Ti,Nb,Zr)Si2O7(O,F)2 P 2₁/a 2/m

09.BE.17 Wohlerite NaCa2(Zr,Nb)Si2O7(O,OH,F)2 P 2₁/m 2/m

09.BE.17 Marianoite! Na2Ca4(Nb,Zr)2(Si2O7)2(O,F)4 P 2₁ 2/m

Other Cuspidine Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

See Also:

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

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Cuspidine

Ca4Si2O7(F,OH)2
Dana No: 56.02.04.03 Strunz No: 09.BE.17
Locality:

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