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Silhydrite

Formula:
3SiO
 
2
·H
 
2
O
System:OrthorhombicColour:White
Hardness:1
Name:Named for its composition: silicon plus water.
This page provides mineralogical data about Silhydrite.

Classification of Silhydrite

IMA status:Approved 1970
Strunz 8th edition ID:8/H.39-10
Nickel-Strunz 10th (pending) edition ID:4.FM.30

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
M : Hydroxides with H2O +- (OH); unclassified
Dana 8th edition ID:75.2.4.1

75 : TECTOSILICATES Si Tetrahedral Frameworks
2 : Si Tetrahedral Frameworks - SiO2 with H2O and organics
Hey's CIM Ref.:7.8.7

7 : Oxides and Hydroxides
8 : Oxides of Si
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Type Occurrence of Silhydrite

Type Locality:Trinite Mining Claim, Trinity Center, Trinity Co., California, USA
General Appearance of Type Material:White, soft, microcrystalline massive material. Material is punky and will float on water when dry (0.65 bulk density). Crystals less than 4 microns in size.
Place of Conservation of Type Material:Smithsonian, USGS Denver Colorado
Year of Discovery:1972
Geological Setting of type material:Spring deposit. Formed by leaching of sodium from magadiite from a cold, highly alkaline brine spring. Also found in caves.
Associated Minerals at type locality:
Magadiite

Physical Properties of Silhydrite

Diaphaneity (Transparency):Transparent
Colour:White
Hardness (Mohs):1
Fracture:Sub-Conchoidal
Density (measured):2.141 g/cm3
Density (calculated):2.116 g/cm3

Crystallography of Silhydrite

Crystal System:Orthorhombic
Cell Parameters:a = 14.51Å, b = 18.8Å, c = 15.93Å
Ratio:a:b:c = 0.772 : 1 : 0.847
Unit Cell Volume:V 4,345.51 ų (Calculated from Unit Cell)

Optical Data of Silhydrite

Type:Biaxial
Dispersion:relatively weak

Chemical Properties of Silhydrite

Formula:
3SiO
 
2
·H
 
2
O
Essential elements:H, O, Si
All elements listed in formula:H, O, Si
Common Impurities:Ti,Al,Fe,Mg,Ca,Na,K,Cl,C

Relationship of Silhydrite to other Species

Related Minerals - Nickel-Strunz Grouping):
4.FM.15Franconite
Na
 
2
Nb
 
4
O
 
11
·9H
 
2
O
4.FM.15Hochelagaite
(Ca,Na,Sr)(Nb,Ti,Si,Al)
 
4
O
 
11
·8H
 
2
O
4.FM.15Ternovite
(Mg,Ca)Nb
 
4
O
 
11
·nH
 
2
O
4.FM.25Belyankinite
Ca
 
1-2
(Ti,Zr,Nb)
 
5
O
 
12
· 9H
 
2
O (?)
4.FM.25Gerasimovskite
(Mn,Ca)(Nb,Ti)
 
5
O
 
12
·9H
 
2
O
4.FM.25Manganbelyankinite
(Mn,Ca)(Ti,Nb)
 
5
O
 
12
·9H
 
2
O
4.FM.35Cuzticite
Fe
3+
2
[TeO
 
6
] · 3H
 
2
O
4.FM.40Cyanophyllite
(Cu,Al)
 
3
[(OH)
 
6
|Sb
5+
 
(OH)
 
6
]
Related Minerals - Hey's Index Grouping:
7.8.1Quartz
SiO
 
2
7.8.2Coesite
SiO
 
2
7.8.3Tridymite
SiO
 
2
7.8.4Stishovite
SiO
 
2
7.8.5Cristobalite
SiO
 
2
7.8.6Lechatelierite
SiO
 
2
7.8.8Opal
SiO
 
2
·nH
 
2
O
7.8.9Mogánite
SiO
 
2

Other Names for Silhydrite

Synonyms:
IMA1970-044
German names:
Silhydrit
Spanish names:
Silhydrita

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Silhydrite

Reference List:Gude, A.J. & R.A. Sheppard (1972), Silhydrite, 3SiO2•H2O, a new mineral from Trinity County, California: American Mineralogist: 57: 1053-1065.

Internet Links for Silhydrite

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    Localities for Silhydrite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
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    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    USA
     
    • California
      • Trinity Co.
        • Trinity Center
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