Jahnsite-(CaMgMg) Mineral Data

[Newest Minerals] [Equipment] [Analytical Services] [About Us] [Mineral Gallery] [eBay Store]
See Also: [Diamond Crystals] [Mineral News] [Hudson Institute] [Minerals on CDROM]
Rare Minerals, Meteorites, Equipment and Analytical Services
Excalibur Mineral Company, World leaders in the supply of rare species
Serving the scientific and collector communities since 1974

General Jahnsite-(CaMgMg) Information

Chemical Formula:

CaMgMg2Fe+++2(PO4)4(OH)2•8H2O

Composition:

Molecular Weight = 782.71 gm

Calcium 5.12 % Ca 7.16 % CaO

Magnesium 9.32 % Mg 15.45 % MgO

Iron 14.27 % Fe 20.40 % Fe₂O₃

Phosphorus 15.83 % P 36.27 % P₂O₅

Hydrogen 2.32 % H 20.71 % H₂O

Oxygen 53.15 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

CaMg₃Fe³⁺₂(PO₄)₄(OH)₂•8(H₂O)

Environment:

Zoned tip on Jahnsite-(NaFeMg). Whiteite-jahnsite group.

IMA Status:

Not Submitted IMA (Dana # Added)

Locality:

Tip Top mine, Custer County, South Dakota, USA. Link to MinDat.org Location Data.

Name Origin:

Named for Richard H. Jahns (1915-1983), mineralogist and pegmatite expert, Stanford University, Palo Alto, California, USA.

Name Pronunciation:

Jahnsite-(CaMgMg)

Synonym:

IMA2007-016

Search for Jahnsite-(CaMgMg) Images

Images:

Image not yet available on Webmineral.com

Try searching images.google.com or Mindat Picture Gallary for mineral pictures. Caution: The images retrieved may not be appropriate.

Jahnsite-(CaMgMg) Crystallography

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/a

Physical Properties of Jahnsite-(CaMgMg)

Color:

Yellow.

Density:

2.58

Diaphaneity:

Transparent

Fracture:

Brittle - Splintery - Brittle fracture leaving splintery fragments.

Habit:

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

Habit:

Striated - Parallel lines on crystal surface or cleavage face.

Hardness:

4 - Fluorite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Jahnsite-(CaMgMg)

Optical Data:

Biaxial (-)

NCalc= 1.64 - from Gladstone-Dale relationship (KC = 0.247) where Ncalc=Dmeas*KC+1

Calculated Properties of Jahnsite-(CaMgMg)

Electron Density:

Bulk Density (Electron Density)=2.60 gm/cc
note: Specific Gravity of Jahnsite-(CaMgMg) =2.58 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_{Jahnsite-(CaMgMg)}= 5.77 barns/electron
U=PE_{Jahnsite-(CaMgMg)} x rElectron Density= 14.99 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Jahnsite-(CaMgMg) is Not Radioactive

Jahnsite-(CaMgMg) Classification

Dana Class:

42.11.03.07 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.11)where (AB)4 (XO4)3 Zq · x(H2O)

(42.11.03)Whiteite Group

42.11.03.01 Whiteite-(CaFeMg) Ca(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2₁/a 2/m

42.11.03.02 Whiteite-(MnFeMg) (Mn,Ca)(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.03.03 Whiteite-(CaMnMg) CaMnMg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.03.04 Rittmannite MnMnFeAl2(OH)2(PO4)4•8(H2O) P 2/a 2/m

42.11.03.05 Jahnsite-(CaFeFe)! (Ca,Mn)(Fe,Mn)Fe2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

42.11.03.06 Jahnsite-(NaFeMg)! NaFeMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

42.11.03.07 Jahnsite-(CaMgMg)! CaMgMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

42.11.03.08 Jahnsite-(NaMnMg)! NaMnMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

Strunz Class:

08.DH.15 08 - PHOSPHATES, ARSENATES, VANADATES

08.D - Phosphates, etc

08.DH -With large and medium-sized cations, (OH, etc.):RO4 < 1:1

08.DH.15 Keckite Ca(Mn,Zn)2Fe3(PO4)4(OH)3•2(H2O) P 2₁/a 2/m

08.DH.15 Jahnsite-(CaMnFe) CaMnFe2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(CaMnMg) CaMnMg2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(CaMnMn) CaMnMn2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(MnMnMn)* MnMnMn2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Kaluginite* (Mn,Ca)MgFe(PO4)2(OH)•4(H2O) C cca 2/m 2/m 2/m

08.DH.15 Rittmannite MnMnFeAl2(OH)2(PO4)4•8(H2O) P 2/a 2/m

08.DH.15 Whiteite-(MnFeMg) (Mn,Ca)(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Whiteite-(CaFeMg) Ca(Fe,Mn)Mg2Al2(PO4)4(OH)2•8(H2O) P 2₁/a 2/m

08.DH.15 Whiteite-(CaMnMg) CaMnMg2Al2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(CaFeFe)! (Ca,Mn)(Fe,Mn)Fe2Fe2(PO4)4(OH)2•8(H2O) P 2/a 2/m

08.DH.15 Jahnsite-(NaFeMg)! NaFeMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

08.DH.15 Jahnsite-(CaMgMg)! CaMgMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

08.DH.15 Jahnsite-(NaMnMg)! NaMnMg2Fe2(PO4)4(OH)2•8H2O P 2/a 2/m

Other Jahnsite-(CaMgMg) Information

References:

NAME( AmMin, v93:940) PHYS. PROP.(AmMin, v93:940) OPTIC PROP.(AmMin, v93:940)

See Also:

Links to other databases for Jahnsite-(CaMgMg) :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - Google Images
4 - Google Scholar
5 - MinDAT
6 - MinMax(Deutsch)
7 - MinMax(English)
8 - Mineralienatlas (Deutsch)
9 - QUT Mineral Atlas
10 - Ruff.Info

Search for Jahnsite-(CaMgMg) using:

[ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Jahnsite-(CaMgMg) :

AA Mineral Specimens

B & L Fine Minerals

Crystalarium.com

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

Dakota Matrix

Diamond Dan Publications

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

Wrights Rock Shop

Translate Jahnsite-(CaMgMg) Mineral Data :

Ask about Jahnsite-(CaMgMg) here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Jahnsite-(CaMgMg) Specimen Label here :

Jahnsite-(CaMgMg)

CaMgMg2Fe+++2(PO4)4(OH)2•8H2O
Dana No: 42.11.03.07 Strunz No: 08.DH.15
Locality:

Notes: