Caswellite
A mixture of two or more distinct mineral species
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About Caswellite
Colour:
Beige, pinkish tan
Lustre:
Resinous, Waxy, Greasy
Hardness:
2½ - 3
Specific Gravity:
3.54
Name:
Named in 1894 by Albert H. (Huntington) Chester (1843-1903) in honour of John Henry Caswell (27 December 1846, New York, New York, USA – 26 October 1909, New York, New York, USA), mineralogist and petrologist at Columbia University, NY, NY, USA (1868-1877). Caswell spent much of his life as a tea merchant, and he assembled a notable mineral collection.
A waxy to resinous material with a foliated appearance and derived from the hydrothermal alteration and replacement of hendricksite mica in the Franklin ore body, Franklin, New Jersey, USA. Both hendricksite and vesuvianite occurred intimately together, and both were partly to completely replaced by grossular. Despite the intimate association of vesuvianite in caswellite replacements, the vesuvianite also exists as large masses in the matrix of the host rock, and it too may be partially to completely replaced by grossular, but the essential appearance of caswellite as a tan lamellar mineral mimicking a mica is not also shown by the co-existing vesuvianite replaced by grossular.
Unique Identifiers
Mindat ID:
43703
Long-form identifier:
mindat:1:1:43703:3
Similar Names
| Castellite | A synonym of Titanite |
Physical Properties of Caswellite
Resinous, Waxy, Greasy
Transparency:
Translucent, Opaque
Colour:
Beige, pinkish tan
Streak:
White
Hardness:
2½ - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Irregular/Uneven
Density:
3.54 g/cm3 (Measured)
Common Associates
Associations Based on Photo Data:
| 22 photos of Caswellite associated with Willemite | Zn2SiO4 |
| 11 photos of Caswellite associated with Andradite | Ca3Fe3+2(SiO4)3 |
| 9 photos of Caswellite associated with Native Lead | Pb |
| 7 photos of Caswellite associated with Vesuvianite | Ca19Fe3+Al4(Al6Mg2)(◻4)◻[Si2O7]4[(SiO4)10]O(OH)9 |
| 7 photos of Caswellite associated with Grossular | Ca3Al2(SiO4)3 |
| 4 photos of Caswellite associated with Bustamite | CaMn2+(Si2O6) |
| 4 photos of Caswellite associated with Margarosanite | Ca2PbSi3O9 |
| 4 photos of Caswellite associated with Barysilite | Pb8Mn2+[Si2O7]3 |
| 4 photos of Caswellite associated with Garnet Group | X3Z2(SiO4)3 |
| 2 photos of Caswellite associated with Celsian | Ba(Al2Si2O8) |
Other Information
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 Caswellite
mindat.org URL:
https://www.mindat.org/min-43703.html
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References for Caswellite
Reference List:
Localities for Caswellite
Showing 3 localities.
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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.
USA | |
| Palache (1935) |
| Phillip Betancourt | |
| Phillip Betancourt |
Franklin Mine, Franklin, Sussex County, New Jersey, USA