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Montroydite

Formula:
HgO
System:OrthorhombicColour:Deep red, brownish red ...
Hardness:1½ - 2
Name:After Montroyd Sharp, an owner of the Terlingua, Texas, USA, mine where it was found.
This page provides mineralogical data about Montroydite.

Classification of Montroydite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:4/A.06-10
Nickel-Strunz 10th (pending) edition ID:4.AC.15

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
A : Metal: Oxygen = 2:1 and 1:1
C : M:O = 1:1 (and up to 1:1.25); with large cations (+- smaller ones)
Dana 8th edition ID:4.2.6.1

4 : SIMPLE OXIDES
2 : AX
Hey's CIM Ref.:7.5.12

7 : Oxides and Hydroxides
5 : Oxides of Zn, Cd and Hg
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Type Occurrence of Montroydite

Type Locality:Terlingua District, Brewster Co., Texas, USA
Year of Discovery:1903

Physical Properties of Montroydite

Lustre:Sub-Adamantine, Vitreous
Diaphaneity (Transparency):Transparent, Translucent, Translucent on thin edges
Colour:Deep red, brownish red to brown; Orange-red to pale yellow in transmitted light, with decreasing thickness
Streak:Yellow-brown
Hardness (Mohs):1½ - 2
Tenacity:Sectile
Cleavage:Perfect
Perfect {010}.
Density (measured):11.23 g/cm3
Density (calculated):11.22 g/cm3

Crystallography of Montroydite

Crystal System:Orthorhombic
Class (H-M):mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:Pmmn (P21/m 21/m 2/n)
Cell Parameters:a = 5.52Å, b = 6.6Å, c = 3.52Å
Ratio:a:b:c = 0.836 : 1 : 0.533
Unit Cell Volume:V 128.24 ų (Calculated from Unit Cell)
Morphology:Long prismatic[001]; also equant or rarely flattened {111}. Terminal faces often striated; on {011} parallel [100], on {201} parallel [101], the pyramids often with several sets of striae. As wormlike, tubular, or spherical aggregates consisting usually of minute prismatic crystals. Massive, pulverulent, or banded. Crystals often bent or twisted.
Twinning:Crystals glide readily: bent-gliding and twist-gliding with T{010} and t[001]; also other, unidentified gliding elements.
Crystal Atlas:
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Montroydite no.1 - Goldschmidt (1913-1926)
Montroydite no.14 - Goldschmidt (1913-1926)

About Crystal Atlas

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The mindat.org Crystal Atlas allows you to view a selection of crystal drawings of real and idealised crystal forms for this mineral and, in certain cases, 3d rotating crystal objects. You need Java to see these. You can download Java for free - click here to download Java

The 3d models and java code are kindly provided by www.smorf.nl. You can control the movement of the models by holding down the left mouse-button over the 3d model and moving your mouse. Keyboard controls are:

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Optical Data of Montroydite

Type:Biaxial (+)
RI values: nα = 2.370 nβ = 2.500 nγ = 2.650
Maximum Birefringence:δ = 0.280

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Very High
Dispersion:relatively strong

Chemical Properties of Montroydite

Formula:
HgO
Essential elements:Hg, O
All elements listed in formula:Hg, O
Analyical Data:Very flexible, but not elastic; somewhat brittle when bent on [010].

Relationship of Montroydite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
4.AC.05Swedenborgite
NaBe
 
4
SbO
 
7
4.AC.10Brownmillerite
Ca
 
2
(Al,Fe
3+
 
)
 
2
O
 
5
4.AC.10Srebrodolskite
Ca
 
2
Fe
 
2
O
 
5
4.AC.20Litharge
PbO
4.AC.20Romarchite
SnO
4.AC.25Massicot
PbO
Related Minerals - Hey's Index Grouping:

- +
7.5.1Zincite
(Zn,Mn
2+
 
,Fe
2+
 
)O
7.5.2Sweetite
Zn(OH)
 
2
7.5.3Ashoverite
Zn(OH)
 
2
7.5.4Wülfingite
Zn(OH)
 
2
7.5.5Gahnite
ZnAl
 
2
O
 
4
7.5.6Hetaerolite
ZnMn
 
2
O
 
4
7.5.7Hydrohetaerolite
ZnMn
 
2
O
 
4
·H
 
2
O
7.5.8Chalcophanite
(Zn,Fe,Mn)Mn
 
3
O
 
7
·3H
 
2
O
7.5.9Woodruffite
Zn(Mn
4+
 
,Mn
3+
 
)
 
5
O
 
10
·3½H
 
2
O
7.5.10Franklinite
Zn
2+
 
Fe
3+
2
O
 
4
7.5.11Monteponite
CdO

Other Names for Montroydite

Other Languages:
German:Montroydit
Russian:Монтроидит
Spanish:Montroydita

Other Information

Health Warning:Contains mercury - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest.

References for Montroydite

Reference List:Moses (1903), American Journal of Science: 16: 259.

Hllebrand and Schaller (1909), USGS Bulletin 405: 47.

Bird (1932), American Mineralogist: 17: 541.

Acta Chemica Scandinavica: 10: 852-866.

Palache, Charles, Harry Berman & Clifford Frondel (1944), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana Yale University 1837-1892, Volume I: Elements, Sulfides, Sulfosalts, Oxides. John Wiley and Sons, Inc., New York. 7th edition, revised and enlarged: 511-514.

Acta Crystallographica (1956): 685.

Articles/Blogs about Montroydite

Internet Links for Montroydite

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  • Look for Montroydite on Wikipedia
  • Look for Montroydite on Mineralien Atlas
  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Montroydite in the Natural History Museum (London) online catalogue
  • Montroydite details from Handbook of Mineralogy (PDF)
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    Localities for Montroydite

    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.
    Italy
     
    • Tuscany
      • Grosseto Province
        • Amiata Mt.
          • Castell'Azzara
    Manfred Kampf collection
      • Siena Province
        • Amiata Mt.
          • Piancastagnaio
    Kyrgyzstan
     
    • Osh Oblast
      • Fergana Valley
        • Alai Range
    [Lapis 1993:11 p11-24]
    [Lapis 11:11-24]
    Mexico
     
    • Guerrero
      • Mun. de Taxco
        • Hauhauxtla
    Panczner (1987): 135-372.
    • Queretaro
      • Mun. de Cadereyta
        • El Doctor (Doctor)
    Panczner (1987): 279.
    Russia
     
    • Eastern-Siberian Region
      • Tuva Republic
        • Pii-Khem District
          • Uyuk Range
    Canadian Mineralogist Feb. 1999
    USA
     
    • Arkansas
      • Pike Co.
    Roberts, A.C. et al (2003), The Canadian Mineralogist: 41(3): 721-725.
    • California
      • San Benito Co.
        • New Idria District
    Canadian Mineralogist: 34: 61-72.
      • San Mateo Co.
    Minerals Of California, 1983, Pemberton, H. E.
        • Redwood City
          • Emerald Lake area
    Pemberton; Minerals of California (1983)
      • Sonoma Co.
    • Nevada
      • Humboldt Co.
        • Opalite District
    NBMG Spec. Pub. 31 Minerals of Nevada
        • Poverty Peak District
    NBMG Spec. Pub. 31 Minerals of Nevada
      • Mineral Co.
        • Borealis District
          • Borealis mine
    NBMG Spec. Pub. 31 Minerals of Nevada
      • Nye Co.
        • Bare Mountain District
    NBMG Spec. Pub. 31 Minerals of Nevada
        • Fairplay District
    NBMG Spec. Pub. 31 Minerals of Nevada
      • White Pine Co.
        • Robinson District
    NBMG Spec. Pub. 31 Minerals of Nevada
    • Texas
      • Brewster Co.
    American Journal of Science, series 4 (1903): 16: 253; Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 52, 90.
    Rocks & Minerals: 66(1): 202.
    Mineral and/or Locality
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