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Micaceous Minerals 3
Not all micaceous looking minerals fall in the MICA group of phyllosilicate minerals. Many of the other silicates appear micaceous but are not. We'll have a look at some of these minerals and hopefully explain the difference. Take a look at our article on Mica and Other Micaceous Minerals.
Roscoelite
- Sold
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- Locality
- Stuckslager mine, El Dorado Co., California, United States
- Formula
- KV3+2(Si3Al)O10(OH)2
- Availability
- Sold
- Size
- 6 x 5 x 2.5 cm - Sm Cabinet
- Tagged
- vanadium
- Special Info
- Type Locality
Fine grained, tiny blackish crystals less than 0.5mm in granular rock. Roscoelite is a vanadium bearing mica.
Roscoelite
- Formula
- KV3+2(Si3Al)O10(OH)2
- Crystal System
- Monoclinic
- Crystal Habit
- Micaceous, Scaly, Massive
- Cleavage
- Perfect, None, None
- Luster
- Pearly
- Color
- brown green, greenish brown, yellow green, dark brown, dark green
- Streak
- greenish white
- Class
- Monoclinic - Prismatic
- Hardness
- 2.5
- Collection
- Phillips Collection
- Special Info
- Type Locality
- Mineralpedia
- View Roscoelite
- On Dakota Matrix
- Previously Sold Roscoelite
- On Dakota Matrix
- Other Available Roscoelite
- WebMineral
- View Roscoelite
- Mindat
- View Roscoelite
Talc
- Sold
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- Locality
- Church Cove, Lizard Peninsula, Cornwall, Englad
- Formula
- Mg3Si4O10(OH)2
- Availability
- Sold
- Size
- 11 x 4 x 2 cm - Cabinet
Soft, tightly packed fibrous greyish green mass. The variety steatite is a low-grade talc with impurities but generally still has the greasy feeling of Talc.
Talc is a phyllosilicate with perfect, easy basal cleavage and is sectile. It is not a mica group mineral and is generally not confused with micas in hand specimen. On a microscopic level, however, the mineral might be confused with micas.
Talc
- Formula
- Mg3Si4O10(OH)2
- Crystal System
- Monoclinic
- Crystal Habit
- Foliated, Scaly, Massive
- Cleavage
- Perfect, None, None
- Luster
- Vitreous - Pearly
- Color
- pale green, white, gray white, yellowish white, brownish white
- Streak
- white
- Class
- Monoclinic - Prismatic
- Fracture
- Uneven
- Hardness
- 1
- Collection
- Phillips Collection
- Mineralpedia
- View Talc
- On Dakota Matrix
- Previously Sold Talc
- On Dakota Matrix
- Other Available Talc
- WebMineral
- View Talc
- Mindat
- View Talc
Zinnwaldite
- Sold
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- Locality
- Irelavour Lithia mine, Hensbarrow Moors, Cornwall, England
- Formula
- K(Al,Fe,Li)3(Si,Al)4O10(OH)F
- Availability
- Sold
- Size
- 8 x 4 x 1.5 cm - Sm Cabinet
A bronzy brown cleavable, micaceous mass.
Zinnwaldite is a phyllosilicate, mica group member. It is an Ordinary (True or Common) Mica - Trioctahderal. It is a lithium bearing transitional member on the Siderophyllite-Polylitionite series.
Zinnwaldite
- Formula
- KLiFe++Al(AlSi3)O10(F,OH)2
- Crystal System
- Monoclinic
- Crystal Habit
- Pseudo Hexagonal, Micaceous, Platy
- Cleavage
- Good, None, None
- Luster
- Vitreous - Pearly
- Color
- light brown, silvery white, gray, yellowish white, greenish white
- Streak
- white
- Class
- Monoclinic - Prismatic
- Fracture
- Uneven
- Hardness
- 3.5-4
- Collection
- Phillips Collection
- On Dakota Matrix
- Previously Sold Zinnwaldite
- On Dakota Matrix
- Other Available Zinnwaldite
- WebMineral
- View Zinnwaldite
- Mindat
- View Zinnwaldite
