Twinnite (original) (raw)

A valid IMA mineral species

About TwinniteHide

This section is currently hidden. Click the show button to view.

Formula:

Pb0.8Tl0.1Sb1.3As0.8S4

Specific Gravity:

5.323 (Calculated)

Crystal System:

Monoclinic

Name:

Named by John L. Jambor in 1967 in honor of Robert Mitchell Thompson (28 July 1918, Moose Jaw, Saskatchewan, Canada - 15 April 1967), professor of mineralogy, University of British Columbia, Vancouver, Canada. He had a special interest in ore minerals and deposits. Thompson means "son of Thomas"; the latter is Aramaic for "a twin". The name is doubly appropriate in alluding to the polysynthetic twinning present in the mineral.

Unique IdentifiersHide

This section is currently hidden. Click the show button to view.

Long-form identifier:

mindat:1:1:4067:5

462a0cd5-125a-40d9-b22d-2a37cc61393e

IMA Classification of TwinniteHide

This section is currently hidden. Click the show button to view.

IMA Formula:

Pb(Sb0.63As0.37)2S4

Type description reference:

Classification of TwinniteHide

This section is currently hidden. Click the show button to view.

2.HC.05a

2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
C : With only Pb

3.7.8.3

3 : SULFOSALTS
7 : ø = 2

5.6.19

5 : Sulphosalts - Sulpharsenites and Sulphobismuthites (those containing Sn, Ge,or V are in Section 6)
6 : Sulpharsenites etc. of Pb alone

Mineral SymbolsHide

This section is currently hidden. Click the show button to view.

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of TwinniteHide

This section is currently hidden. Click the show button to view.

Hardness:

VHN50=131 - 152 kg/mm2 - Vickers

Density:

5.323 g/cm3 (Calculated)

Optical Data of TwinniteHide

This section is currently hidden. Click the show button to view.

Reflectivity:

Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 45.2%.
R1 shown in black, R2 shown in red

Colour in reflected light:

white

Comments:

displays twin lamellae

Chemistry of TwinniteHide

This section is currently hidden. Click the show button to view.

Mindat Formula:

Pb0.8Tl0.1Sb1.3As0.8S4

Simplified Pb(Sb,As)2S4.

Crystallography of TwinniteHide

This section is currently hidden. Click the show button to view.

Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 7.997(2) Å, b = 19.517(5) Å, c = 8.634(2) Å
β = 91.061(4)°

Ratio:

a:b:c = 0.41 : 1 : 0.442

Unit Cell V:

1,347.34 ų (Calculated from Unit Cell)

Twinning:

Polysynthetic, with composition plane parallel to {100}.

Comment:

Space group P21/n. Originally assumed to be triclinic, with the cell parameters 19.58, 7.98, 8.56 A, 89.77, 89.62 and 90.27°.

Crystal StructureHide

This section is currently hidden. Click the show button to view.

Load
Unit Cell |Unit Cell Packed
2x2x2 |3x3x3 |4x4x4

Show
Big Balls |Small Balls |Just Balls |Spacefill
Polyhedra Off |Si Polyhedra |All Polyhedra
Remove metal-metal sticks

Display Options
Black Background |White Background
Perspective On |Perspective Off
2D |Stereo |Red-Blue |Red-Cyan

View
CIF File Best |x |y |z |a |b |c

Rotation
Stop |Start

Labels
Console Off |On |Grey |Yellow

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

This section is currently hidden. Click the show button to view.

Powder Diffraction Data:

Geological EnvironmentHide

This section is currently hidden. Click the show button to view.

Type Occurrence of TwinniteHide

This section is currently hidden. Click the show button to view.

General Appearance of Type Material:

Two megascopic grains, the larger about 1.5 mm in diameter, and four microscopic grains.

Place of Conservation of Type Material:

Canadian Geological Survey, Ottawa, Canada, 12175.
Canadian Museum of Nature, Ottawa, Canada.

Reference:

Jambor, J.L. (1967) New lead sulfantimonides from Madoc, Ontario. 2. Mineral descriptions. The Canadian Mineralogist: 9: 191-213.

Synonyms of TwinniteHide

This section is currently hidden. Click the show button to view.

Other Language Names for TwinniteHide

This section is currently hidden. Click the show button to view.

Relationship of Twinnite to other SpeciesHide

This section is currently hidden. Click the show button to view.

Other Members of this group:

Common AssociatesHide

This section is currently hidden. Click the show button to view.

Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

This section is currently hidden. Click the show button to view.

Other InformationHide

This section is currently hidden. Click the show button to view.

Notes:

KOH rapidly tarnishes twinnite iridescent and leaves a characteristic flat brownish grey colour when the reagent is rubbed off. 1:1 HNO3, rapidly tarnishes the mineral black. Other reagents test negative.

Health Risks:

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

Internet Links for TwinniteHide

This section is currently hidden. Click the show button to view.

References for TwinniteHide

This section is currently hidden. Click the show button to view.

Reference List:

Makovicky, E., Topa, D., Tajjedin, H., Rastad, E., Yaghubpur, A. (2012) The crystal structure of guettardite, PbAsSbS4, and the twinnite-guettardite problem. The Canadian Mineralogist, 50 (2) 253-265 doi:10.3749/canmin.50.2.253

Localities for TwinniteHide

This section is currently hidden. Click the show button to view.

This 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.

Locality ListHide

This section is currently hidden. Click the show button to view.

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.