Pyrophyllite is a soft mineral belonging to the group of silicates, specifically to the group of phyllosilicate clay minerals, that is, it is a clay. Its name comes from the Greek pyr, which means “fire”, and phyllos, which means “leaf”, alluding to the way in which the mineral exfoliates when exposed to high temperatures.
It was discovered at the Berezovskoye goldfield, located in Sverdlovsk Oblast, Russia, and was first described by R. Hermann.
If you want to know all the information about this mineral, including its physical and chemical properties, its most important deposits and its many scientific and industrial applications, you have come to the right place.
Physical and chemical properties of the mineral pyrophyllite
The mineral pyrophyllite is a hydrated aluminum silicate whose chemical formula is AltwoYes4EITHER10(oh)two. Its main colors are white, light green or apple, gray, brown, yellow and light blue.
The hardness of the mineral is 1 to 2 on the Mohs scale. Its crystalline system is monocyclic., although specimens with identical properties and triclinic crystal systems can be obtained. Gloss is greasy to dull, but may be pearly on some cleavage surfaces.
| Pyrophyllite | Physical and chemical properties |
|---|---|
| Chemical formula | Al2Si4O10(OH)2 |
| Class, group | Silicates, phyllosilicates, clay |
| Composition | basic aluminum silicate |
| Color | White, light green, apple green, grey, yellow, brown, light blue |
| Stripe | white |
| Mohs hardness | 1-2 |
| Crystalline system | monoclinic |
| Transparency | translucent to opaque |
| specific gravity | 2.8 – 2.9 |
| Gloss | Pearly |
| Fracture | chipped,uneven |
| Tenacity | flexible but inelastic |
| Other identification marks | 1) It has a greasy feel. 2) May be fluorescent yellow in longwave ultraviolet light. |
| Most striking features | Distinctive crystal habits, light weight and greasy feel. |
| Environment | In metamorphic schists and hydrothermal replacement deposits. |
The crystals are translucent to opaque, and occur in radiating dense masses, often shaped like fans that connect to each other. They can also be found in compacted veins, rosettes, and radial balls. Visible radiant crystals can usually be found.
Pyrophyllite has the same physical properties as the mineral talc. Both are isomorphic, which means that they share the monocyclic crystal structure but their chemistry is different. Talc contains magnesium instead of aluminum.
Pyrophyllite in hydrothermal alterations
When the mineral pyrophyllite dominates the outcrop, the rock will be soft, waxy, massive, and not have a defined texture. It is quite common for pyrophyllite to occur with quartz and other minerals, and the rock may retain primary textures.
It must be taken into account that the pyrophyllite-rich alteration shows strong foliation in deformed areas.
Identification of pyrophyllite clay
Pyrophyllite is usually white to tan in color and can be detected by a soapy feel to fractures with fingers. When this mineral predominates, it can form the supported matrix of breccias or generalized alteration envelopes around hydrothermal veins or veins.
Geological setting and genesis
Pyrophyllite is a characteristic mineral of advanced argillic alteration that results from the reaction of low pH fluids with rocks.
The mineral forms at temperatures intermediate between kaolinite and andalusite (~200-350 °C) and is therefore important in the deepest parts of some high-sulfidation epithermal deposits and in the upper parts of some high-sulfidation systems. porphyry.
Pyrophyllite is also found in some gold deposits associated with strong deformation, although the timing of pyrophyllite crystallization is uncertain.
Also this mineral is formed through the metamorphism of aluminous rocks, which may represent previous alteration (zones of surface acid leaching or high sulphidation above boiling geothermal systems), weathered regoliths or some aluminum-rich sedimentary rocks.
Deposits of clay
Notable localities of the mineral include Australia, Italy, Switzerland and the United States. Collectible specimens usually come from North Carolina, while the yellow variety is usual for Gundagai, New south Wales.
Meaning and properties of the pyrophyllite stone
Esoteric beliefs affirm that the pyrophyllite gem activates the solar plexus and unites it with the sacral chakras, which contributes to raising creativity and sexual energy, while strengthening people’s self-confidence.
It is believed that this mineral can help people with low self-esteem and feelings of sadness, since it can “ignite the internal fire” to boost positive emotions.
From a metaphysical point of view, Pyrophyllite is considered an ideal gem to channel negative ideas and work towards desired goals. For many cultures, it is a “creative rock.” It is important to clarify that these statements belong to popular belief and They have no scientific basis.
Uses of the mineral pyrophyllite
Pyrophyllite has various applications in the paint, ceramics, insecticide and rubber industry. In enamels, this mineral represents a major source of SiOtwothan quartz, as long as its iron content is tolerable.
Pyrophyllite is often used as an ingredient in wall tiles due to its ability to reduce the spread of moisture.
Thanks to its physical properties and its stable nature, this stone can be used in casting release agents and in structural clay products. Also, it is a good material for certain refractories because it does not require calcination.
Its properties also allow reduce wear and tear on machinery and molds used with dry and wet products. Pyrophyllite can be used as a minor ornamental gem in sculptures and carvings.