There is some questions about if it's pyrophyllite or some other mineral.
|Mineral class||Silicates : Phyllosilicates : Serpentinite - talc - Pyrophyllite group|
|Habitus||As radiating groups of soft lamellaes. Often as massive aggregates.|
|Cleavage||Good. (Massive variants none.)|
|Hardness||1-2 (Could contain other minerals, making it harder.)|
|Color||Yellowish white to yellowish brown, light green.|
|Luster||Pearly, massive forms greasy.|
|Description|| Pyrophyllite is used as talc sometimes,
but since talc is better and cheaper it's use is limited.|
The main usage of pyrophyllite is as a carrier for insectoides and is used as a filler in these products.
|Occurance|| Created through hydrothermal transformation of
aluminum rich rocks. Light green masses of serpentinite looking minerals
are often pyrophyllite.|
Andalusite in quartz is often coated by soft yellow pyrophyllite.
|Notes|| The lamellaes are bendable but are not flexible.|
The name comes from the Greek words pyro (fire) and phyllos (leaf), since it expands when heated and falls apart in thin leafs.
It is very hard to discern pyrophyllite from talc without chemical methods. One method is to test for aluminum with the aid of a cobalt nitrate solution. A few drops are applied at the sample and then heating the sample until it glows. If the sample changes to a blue color it is pyrophyllite, if it turns violet it is talc.
A good reference is "Mineral och Bergarter" by Erich Spicar, page 81.
|Locations|| A not so rare mineral, often mistaken as talc. |
| To silicate index.
|| Mineral group index.
If you have some questions, suggestions or comments you are welcome to write me a line or two.