Phoenicochroite
A valid IMA mineral species - grandfathered
This page is currently not sponsored. Click here to sponsor this page.
About Phoenicochroite
Formula:
Pb2(CrO4)O
Colour:
Dark red, bright red
Lustre:
Adamantine, Resinous
Hardness:
2½ - 3½
Specific Gravity:
7.01
Crystal System:
Monoclinic
Name:
From the Greek φοίυικος for "deep red" and χρόα for "colour," in allusion to its colour.
Type Locality:
Isostructural with:
This page provides mineralogical data about Phoenicochroite.
Unique Identifiers
Mindat ID:
3194
Long-form identifier:
mindat:1:1:3194:9
IMA Classification of Phoenicochroite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Pb2+2O(Cr6+O4)
Approval year:
1980
Classification of Phoenicochroite
7.FB.05
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
F : Chromates
B : With additional O,V, S, Cl
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
F : Chromates
B : With additional O,V, S, Cl
Dana 7th ed.:
35.1.2.1
35.1.2.1
35 : ANHYDROUS CHROMATES
1 : A2XO4
35 : ANHYDROUS CHROMATES
1 : A2XO4
27.2.6
27 : Sulphites, Chromates, Molybdates and Tungstates
2 : Chromates
27 : Sulphites, Chromates, Molybdates and Tungstates
2 : Chromates
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Phc | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Phoenicochroite
Adamantine, Resinous
Transparency:
Translucent
Comment:
Glimmering
Colour:
Dark red, bright red
Comment:
Turns lemon-yellow on exposure.
Streak:
Brick-red to yellowish orange
Hardness:
2½ - 3½ on Mohs scale
Tenacity:
Sectile
Cleavage:
Perfect
Perfect on {201}; poor on {001}, {010}, {011}.
Perfect on {201}; poor on {001}, {010}, {011}.
Density:
7.01 g/cm3 (Measured) 7.075 g/cm3 (Calculated)
Optical Data of Phoenicochroite
Type:
Biaxial (+)
RI values:
nα = 2.34 - 2.38 nβ = 2.38 - 2.44 nγ = 2.65
2V:
Measured: 58° , Calculated: 60°
Max. Birefringence:
δ = 0.270 - 0.310
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v, moderately strong to strong
Optical Extinction:
X = b; Y ∧ c = –2°; Z ∧ c = 88°.
Pleochroism:
Weak
Comments:
Absorption: X < Y < Z.
Chemistry of Phoenicochroite
Mindat Formula:
Pb2(CrO4)O
Element Weights:
Elements listed:
Crystallography of Phoenicochroite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 14.001(7) Å, b = 5.675(3) Å, c = 7.137(5) Å
β = 115.22°
β = 115.22°
Ratio:
a:b:c = 2.467 : 1 : 1.258
Unit Cell V:
513.02 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals tabular and imperfect, often reticularly intergrown. Massive; thin coatings.
Tabular on {100} or {201}, elongated along [010] or [001], showing {010}, {100}, {110}, {201}, {211}, {310}.
Tabular on {100} or {201}, elongated along [010] or [001], showing {010}, {100}, {110}, {201}, {211}, {310}.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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
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
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0000204 | Phoenicochroite | Williams S A, McLean W J, Anthony J W (1970) A study of phoenicochroite - its structure and properties American Mineralogist 55 784-792 |  | 1970 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.39 Å | (100) |
| 2.989 Å | (100) |
| 3.60 Å | (70) |
| 6.40 Å | (40) |
| 3.26 Å | (40) |
| 4.42 Å | (30) |
| 2.840 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45b : [Other oxidized fumarolic minerals] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Phoenicochroite
Associated Minerals at Type Locality:
Synonyms of Phoenicochroite
Other Language Names for Phoenicochroite
Varieties of Phoenicochroite
| Berezovite | Discredited - shown to be altered phoenicochroite by S.A. Williams (1974). |
Common Associates
Associations Based on Photo Data:
| 39 photos of Phoenicochroite associated with Hemihedrite | Pb10Zn(CrO4)6(SiO4)2(OH)2 |
| 28 photos of Phoenicochroite associated with Schwartzembergite | Pb5H2(IO2)O4Cl3 |
| 26 photos of Phoenicochroite associated with Wulfenite | Pb(MoO4) |
| 17 photos of Phoenicochroite associated with Mimetite | Pb5(AsO4)3Cl |
| 14 photos of Phoenicochroite associated with Seeligerite | Pb3(IO3)OCl3 |
| 14 photos of Phoenicochroite associated with Pyromorphite | Pb5(PO4)3Cl |
| 12 photos of Phoenicochroite associated with Iranite | Pb10Cu(CrO4)6(SiO4)2(OH)2 |
| 8 photos of Phoenicochroite associated with Wickenburgite | CaPb3Al2Si10O24(OH)6 |
| 8 photos of Phoenicochroite associated with Vauquelinite | Pb2Cu(CrO4)(PO4)(OH) |
| 7 photos of Phoenicochroite associated with Crocoite | PbCr6+O4 |
Related Minerals - Strunz-mindat Grouping
| 7.FB.05 | Georgerobinsonite | Pb4(CrO4)2(OH)2FCl |
| 7.FB.10 | Santanaite | Pb11(CrO4)O12 |
| 7.FB.15 | Wattersite | [Hg2]2+2Hg2+[CrO4]O2 |
| 7.FB.20 | Deanesmithite | [Hg2]2+Hg2+3[CrO4]S2O |
| 7.FB.25 | Edoylerite | Hg2+3(CrO4)S2 |
| 7.FB.30 | Reynoldsite | Pb2Mn4+2O5(CrO4) |
Other Information
Notes:
Soluble in HCl with separation of lead chloride.
Health Risks:
Chromate minerals contain the carcinogenic and mutagenic chromate ion. Always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Do not pour chromate-containing solutions down the drain.
Internet Links for Phoenicochroite
mindat.org URL:
https://www.mindat.org/min-3194.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Phoenicochroite
Reference List:
Hermann, R. (1833) Ueber den Melanochroït, ein neues Mineral. Annalen der Physik und Chemie, 104. 162-164 doi:10.1002/andp.18331040516(as Melanochroit)
Larsen, Esper S. (1921) The microscopic determination of the nonopaque minerals. Bulletin 679. US Geological Survey doi:10.3133/b679 p.119
Williams, Sidney A., McLean, W. John, Anthony, John W. (1970) A study of phoenicochroite - its structure and properties. American Mineralogist, 55 (5-6) 784-792
Cesbron, Fabien, Williams, Sydney A. (1980) Iranite˗hémihédrite, bellite, phoenicochroite, vauquelinite et fornacite : synthèse et nouvelles données. Bulletin de Minéralogie, 103 (5) 469-477 doi:10.3406/bulmi.1980.7409
Localities for Phoenicochroite
Showing 49 localities.
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
Quick NavTopAbout PhoenicochroiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesVarietiesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Unión Minera mine, Caracoles, Caracoles mining district, Sierra Gorda, Antofagasta Province, Antofagasta, Chile