Oct 21 2013
Troilite is a rare iron sulfide mineral and a member of the pyrrhotite group. Although it can be found on Earth, it is more abundant in meteorites.
Domenico Troili collected and studied the samples of the mineral when a meteorite fall was observed in 1766 at Albareto, Italy. Later, in 1862, Gustav Rose, a German mineralogist analyzed the material and recognized it as stoichiometric iron sulfide. It was named after Domenico Troili who first discovered it.
Properties of Troilite
The following are the key properties of Troilite:
- Cell Data
- Space Group: P63/mmc
- a = 5.958
- c = 11.74
- Z = 12
- Crystal Data
- Hexagonal
- Point Group: 6/m 2/m 2/m
- Massive, granular; nodular
- X-ray Powder Pattern: 2.09 (100), 2.66 (60), 1.719 (50), 2.98 (40), 1.331 (40), 1.119 (40), 1.923 (30)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
Content 3 |
| Fe |
62.70 |
63.0 |
63.53 |
| S |
35.40 |
35.0 |
36.47 |
| Total |
98.10 |
98.0 |
100.00 |
- Optical Properties
- Estimated Properties
| Electron density |
Bulk density (electron density)=4.69 g/cm3
note: Specific gravity of Troilite =4.91 g/cm3 |
| Photoelectric |
PETroilite = 21.27 barns/electron
U= PETroilite x ρElectron density= 99.79 barns/cm3 |
| Fermion index |
Fermion index = 0.01
Boson index = 0.99 |
| Radioactivity |
Troilite is not radioactive |
How to Identify Troilite
Troilite is commonly observed in bronze brown or gray brown colors. It is opaque and non- fluorescent with gray black streak, metallic luster, and strong magnetic properties.
Its fractures are uneven at flat surfaces. It can be found in massive, tabular or platy forms. The average density of troilite is 4.61 g/cm3, and its relative hardness varies from 3.5 to 4.
Global Distribution
Troilite is distributed in the following places:
- Alta mine, Del Norte Co., California, USA
- Wannaway Fe–Ni–Cu deposit and Sally Malay Cu–Ni deposit, Western Australia
- Panzhihua-Xichang district, Sichuan Province, China
- Disco Island and the Ilimaussaq intrusive, southern Greenland
- Nordfjellmark, Norway.
Occurrence of Troilite and Useful Mineral Associations
Troilite occurs in serpentine (Del Norte Co., California, USA), a layered ultramafic intrusive (Sally Malay deposit, Australia) with Fe–Cu–Ni sulfides and as nodules in meteorites. It is closely associated with silicates, phosphates, graphite, sphalerite, chromite, daubréelite, pyrite, chalcopyrite, valleriite, cubanite, mackinawite, pentlandite and pyrrhotite.
References