Danburite Mineral Data

General Danburite Information

Chemical Formula:

CaB2(SiO4)2

Composition:

Molecular Weight = 245.86 gm

Calcium 16.30 % Ca 22.81 % CaO

Silicon 22.85 % Si 48.88 % SiO₂

Boron 8.79 % B 28.32 % B₂O₃

Oxygen 52.06 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaB₂Si₂O₈

Environment:

Contact metamorphic rocks.

IMA Status:

Valid Species (Pre-IMA) 1839

Locality:

Danbury, Connecticut. Link to MinDat.org Location Data.

Name Origin:

Named after its location.

Name Pronunciation:

Danburite + Pronunciation

Synonym:

ICSD 6254

PDF 29-304

Danburite Image

Images:

Danburite

Comments: Very-fine, large, single transparent crystal of danburite with minor crystals of colorless calcite all around the base.
Location: Charcas, San Luis Potosi, Mexico. Scale: 4 x 2.5 x 9.5 cm.
© Dan Weinrich

Danburite Crystallography

Axial Ratios:

a:b:c =0.9184:1:0.8822

Cell Dimensions:

a = 8.048, b = 8.763, c = 7.731, Z = 4; V = 545.23 Den(Calc)= 3.00

Crystal System:

Orthorhombic - DipyramidalH-M Symbol (2/m 2/m 2/m) Space Group: Pnam

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

By Intensity(I/I_o): 3.564(1), 2.654(0.75), 2.961(0.7),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Phillips M W , Gibbs G V , Ribbe P H , American Mineralogist , 59 (1974) p.79-85, The crystal structure of danburite: A comparison with anorthite, albite, and, reedmergnerite

Physical Properties of Danburite

Cleavage:

{001} Poor

Color:

Colorless, White, Gray, Brownish white, Straw yellow.

Density:

2.97 - 3.02, Average = 2.99

Diaphaneity:

Transparent to translucent

Fracture:

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

Habit:

Disseminated - Occurs in small, distinct particles dispersed in matrix.

Habit:

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

Habit:

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

Hardness:

7 - Quartz

Luminescence:

Fluorescent and thermoluminescent (red), Short UV=violet blue, Long UV=blue to blue-green.

Luster:

Vitreous - Greasy

Streak:

white

Optical Properties of Danburite

Gladstone-Dale:

CI meas= -0.004 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.211,KPDmeas= 0.2114,KC= 0.2104
Ncalc = 1.63 - 1.64

Optical Data:

Biaxial (+/-), a=1.63, b=1.633, g=1.636, bire=0.0060, 2V(Calc)=88, 2V(Meas)=88-90. Dispersion relatively strong.

Calculated Properties of Danburite

Electron Density:

Bulk Density (Electron Density)=2.98 gm/cc
note: Specific Gravity of Danburite =3.00 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Danburite= 2.99 barns/electron
U=PE_Danburite x rElectron Density= 8.89 barns/cc.

Radioactivity:

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

Danburite Classification

Dana Class:

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

(56.03)with [Si2O7] with borate groups

(56.03.01)Danburite Goup

56.03.01.01 Danburite CaB2(SiO4)2 Pnam 2/m 2/m 2/m

56.03.01.02 Maleevite! BaB2Si2O8 P nma 2/m 2/m 2/m

56.03.01.03 Pekovite! SrB2Si2O8 P nma 2/m 2/m 2/m

Strunz Class:

09.FA.65 09 - SILICATES (Germanates)

09.F - Tektosilicates without Zeolitic H2O

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

09.FA.65 Danburite CaB2(SiO4)2 Pnam 2/m 2/m 2/m

09.FA.65 Maleevite! BaB2Si2O8 P nma 2/m 2/m 2/m

09.FA.65 Pekovite! SrB2Si2O8 P nma 2/m 2/m 2/m

Other Danburite Information

References:

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

See Also:

Links to other databases for Danburite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - CalTech Mineral Spectroscopy
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Glendale Community College
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - HyperPhysics
14 - MinDAT
15 - Mineralienatlas (Deutsch)
16 - Online Mineral Museum
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - Tradeshop.com - The Rainbow of Gems
20 - WWW-MINCRYST
21 - theimage

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Ask about Danburite here :
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Print or Cut-and-Paste your Danburite Specimen Label here :

Danburite

CaB2(SiO4)2
Dana No: 56.03.01.01 Strunz No: 09.FA.65
Locality:

Notes: