Hydromagnesite Mineral Data

General Hydromagnesite Information

Chemical Formula:

Mg5(CO3)4(OH)2•4(H2O)

Composition:

Molecular Weight = 467.64 gm

Magnesium 25.99 % Mg 43.09 % MgO

Hydrogen 2.16 % H 19.26 % H₂O

Carbon 10.27 % C 37.64 % CO₂

Oxygen 61.58 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₅(CO₃)₄(OH)₂•4(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1835

Locality:

Castle Point, Hoboken, Hudson County, New Jersey, USA Link to MinDat.org Location Data.

Name Origin:

Named after its chemical composition.

Name Pronunciation:

Hydromagnesite + Pronunciation

Synonym:

ICSD 920

PDF 25-513

Hydromagnesite Image

Images:

Hydromagnesite

Comments: White, blocky crystals of hydromagnesite.
Location: Lobming, Styria, Austria. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Pokrovskite Hydromagnesite

Comments: Tan spherical pokrovskite on serpentinite rock with white hydromagnesite sprays.
Location: KCA Quarry, San Benito County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Hydromagnesite Crystallography

Axial Ratios:

a:b:c =1.1308:1:0.9373

Cell Dimensions:

a = 10.11, b = 8.94, c = 8.38, Z = 2; beta = 114.58° V = 688.78 Den(Calc)= 2.25

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): 5.79(1), 2.899(0.82), 9.2(0.39),

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Forms: ( 1 1 0) ( 0 1 1) ( 1 0 0)

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Physical Properties of Hydromagnesite

Cleavage:

{010} Perfect, {100} Distinct

Color:

Colorless, White.

Density:

2.16 - 2.2, Average = 2.18

Diaphaneity:

Transparent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Hardness:

3.5 - Copper Penny

Luminescence:

Fluorescent, Short UV=green, Long UV=bluish white.

Luster:

Silky

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Hydromagnesite

Gladstone-Dale:

CI meas= -0.055 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.022 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2363,KPDmeas= 0.2439,KC= 0.2311
Ncalc = 1.5 - 1.52

Optical Data:

Biaxial (+), a=1.523, b=1.527, g=1.545, bire=0.0220, 2V(Calc)=52, 2V(Meas)=30-90. Dispersion none.

Pleochroism (x):

none.

Pleochroism (y):

none.

Pleochroism (z):

none.

Calculated Properties of Hydromagnesite

Electron Density:

Bulk Density (Electron Density)=2.29 gm/cc
note: Specific Gravity of Hydromagnesite =2.25 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_{Hydromagnesite}= 0.77 barns/electron
U=PE_{Hydromagnesite} x rElectron Density= 1.76 barns/cc.

Radioactivity:

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

Hydromagnesite Classification

Dana Class:

16b.07.01.01 (16b)Carbonates - Hydroxyl or Halogen

(16b.07)Dana Type

(16b.07.01)Dana Group

16b.07.01.01 Hydromagnesite Mg5(CO3)4(OH)2•4(H2O) P 2₁/c 2/m

16b.07.01.02 Widgiemoolthalite (Ni,Mg)5(CO3)4(OH)2•4-5(H2O) P 2₁/c 2/m

Strunz Class:

05.DA.05 05 - CARBONATES (NITRATES)

05.D - Carbonates with Additional Anions, with H2O

05.DA -With medium-sized cations

05.DA.05 Dypingite Mg5(CO3)4(OH)2•5(H2O) Unk. Mono

05.DA.05 Giorgiosite Mg5(CO3)4(OH)2•5(H2O) ? Mono

05.DA.05 Hydromagnesite Mg5(CO3)4(OH)2•4(H2O) P 2₁/c 2/m

05.DA.05 Widgiemoolthalite (Ni,Mg)5(CO3)4(OH)2•4-5(H2O) P 2₁/c 2/m

Other Hydromagnesite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

See Also:

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

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

Hydromagnesite

Mg5(CO3)4(OH)2•4(H2O)
Dana No: 16b.07.01.01 Strunz No: 05.DA.05
Locality:

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