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Holtstamite (Holtstamit)

Collectors Summary

Color blass bräunlichgelb
Streak color weiß
Lustre Glasglanz
Hardness (Mohs) 5 - 6
Cleavages ohne deutliche Richtungen
Fracture muschelig
Crystal System tetragonal, I41/acd

Chemism

Chem­ical formula

{Ca3}[Al2](Si2)(☐)O8(OH)4

Chem­ical com­po­si­tion

Aluminium, Calcium, Silicium, Sauerstoff, Wasserstoff, Vakanz

Unit weight: 426.39428441 u; Number of atoms in the formula: 24

Info

Empirical formula:

{Ca3}[Al2](Si2)(Vc)O8(OH)4

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)
Vacancy

Vc

0.00

1

4.17

0.0000000

0.0000000
Hydrogen

H

0.95

4

16.67

1.0079470

4.0317880
Oxygen

O

45.03

12

50.00

15.9994300

191.9931600
Aluminium

Al

12.66

2

8.33

26.9815382

53.9630764
Silicon

Si

13.17

2

8.33

28.0855300

56.1710600
Calcium

Ca

28.20

3

12.50

40.0784000

120.2352000

Anal­y­sis wt%

SiO2 : 26.26, Al2O3 : 10.77, Fe2O3 : 6.30, Mn2O3 : 11.64, CaO : 36.76, H2O : 7.87 (Ref: European Journal of Mineralogy 2005)

Strunz 9th edi­tion incl. updates

9.AD.25

9: Silikate (Germanate)
A: Inselsilikate (Nesosilikate)
D: Insel(Neso)silikate ohne weitere Anionen; Kationen in oktahedraler [6] und gewöhnlich größerer Koordination
25:Granat-Gruppe

Lapis Clas­sifica­tion

VIII/A.08-210

VIII: SILIKATE
A: Inselsilikate mit [SiO4] 4--Baugruppen
8: Kationen in kubischer und oktaedrischer Koordination [8+6]; Granat-Gruppe

Clas­sifica­tion by Hölzel

9.AC.730

9: SILICATES
A: Nesosilicates
C: Garnet-Group
7: Hydrogarnets

IMA sta­tus

anerkannt 2003

Min­eral sta­tus

anerkanntes Mineral

IMA Classification

IMA Clas­sifica­tion

 Garnet supergroup  ⇒ Silicate garnets; Henritermierite group (Z charge 8)

Optical Properties

Color

blass bräunlichgelb

Streak color

weiß

Diaphane­ity (Trans­parency)

transparent

Lus­tre

Glasglanz

max. Birefrin­gence

0.028
Birefringence chart\! Holtstamite title=Birefringence chart Holtstamite

Michel-Levy Color Chart viewed according to the maximum birefringence (at 30μm). Mineral color is not taken into account. Click on the image to enlarge or change thickness.

RI value α / ω / n

1.718

RI value γ / ε

1.746

Ri mean

1.727

2V angle

Uniaxial (+)

Crystallography

Crystal Sys­tem

tetragonal

Class (H-M)

4/mmm

Space Group number

142

Space Group

I41/acd

Cell param­e­ters a (Å)

12.337

Cell param­e­ters b (Å)

-

Cell param­e­ters c (Å)

11.930

Cell param­e­ters a/b or c/a

0.967

Cell param­e­ters c/b

-

Cell param­e­ters α

90°

Cell param­e­ters β

90°

Cell param­e­ters γ

90°

Z

8

Volumne (ų)

1815.765

X-Ray Pow­der Diffrac­tion

3.08(44), 2.978(45), 2.757(55), 2.743(100), 2.685(54), 2.501(47), 1.614(56)
XRD chart Holtstamite

Calculated from d-spacing and intensity at 0.1541838 nm (Cu)

Crystal Structure 3D

Open larger view

Physical Properties

Hard­ness (Mohs)

5 - 6

VHN (Hard­ness Vick­ers)

730 (ungefähre Angabe abgeleitet aus der Mohshärte)

Density (g/cm³)

3.25

3.119 ( ρ calc. Mineralienatlas )

Cleav­ages

ohne deutliche Richtungen

Frac­ture

muschelig

Tenac­ity

spröde

(Co-)Type locality

(Co-)Type locality

Südafrika/Nordkap (Northern Cape), Provinz/Kalahari Manganese Field/Hotazel/Wessel's Mine (Wessels Mine)

Preface

Rare­ness

sehr selten

Author (Name, Year)

Hålenius & Häussermann & Harryson, 2005

References

European Journal of Mineralogy 17 (2005), 375.

Grew, E.S., Locock, A.J., Mills, S.J., Galuskina, I.O., Galuskin, E.V., Halenius, U., 2012; Nomenclature of the garnet supergroup. American Mineralogist; preprint December 2012 - [Formel].

IMA group assignments

 
Garnet supergroup
{X3}[Y2](Z3)φ12
 
 

 
 
Silicate garnets; Henritermierite group (Z charge 8)
 
 
 

 
 
 
Henritermierite
{Ca3}[Mn3+2](Si2)(☐)O8(OH)4
tetragonal
I41/acd

 
 
 
Holtstamite
{Ca3}[Al2](Si2)(☐)O8(OH)4
tetragonal
I41/acd

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Actuality: 20. May 2022 - 02:17:11

Other languages

German

Holtstamit

Spanish

Holtstamita

French

Holtstamite

English

Holtstamite

Russian

Хольтстамит

Russian

Хольцтамите

Traditional Chinese

四方水鈣榴石

Simplified Chinese

四方水钙榴石

CNMNC (IMA)-Number

IMA 2003-047

CNMNC symbol

Symbol

Hts

Automatic Links to external internet sources (Responsibility is with the operator)

German pages

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English pages

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RRUFF - References and PDF downloads - search for: Holtstamite
American-Mineralogist-Crystal-Structure-Database - search for: Holtstamite
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Russian pages

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Mineral Dealer

German pages

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