mineral specimens
rare minerals
mineral dealer
systematic minerals
Black Hills minerals
fine minerals
mineral dealer
Dana minerals
IMA minerals
mineral collections
rock and minerals
gem crystal
0 item @ $0.00  

Micaceous Minerals 2

Monday, 10 April 2017 08:00 AM

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.

Margarite

#DP46710
Locality
Chester Emery mines, Hampden Co., Massachusetts, United States 
Formula
CaAl2(Si2Al2)O10(OH)2 
Availability
Sold
Size
5 x 3 x 3 cm - Miniature 

Light purplish micaceous crystals to 2cm. This is the same as the prior Margarite in this Special Edition, just a bit smaller.


Margarite

Formula
CaAl2(Si2Al2)O10(OH)2 
Crystal System
Monoclinic 
Crystal Habit
Lamellar, Massive - Lamellar, Scaly 
Cleavage
Good, None, None 
Luster
Pearly 
Color
white, gray, pinkish gray, yellowish gray 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Brittle 
Hardness
Collection
Polak Collection
Mineralpedia
View Margarite
On Dakota Matrix
Previously Sold Margarite
On Dakota Matrix
Other Available Margarite
WebMineral
View Margarite
Mindat
View Margarite
SOLD
Masutomilite - 46464
Masutomilite - 46464

Masutomilite

#46464
Locality
Mokrusha pegmatite, Alabashka peg. field, Murzinka dist., Middle Urals, Russia 
Formula
KLiAlMn2+(Si3Al)O10(F,OH)2 
Availability
Sold
Size
6 x 4 x 2 cm - Sm Cabinet 
Special Info
XRD Confirmed 
Special Info
EDS Confirmed 

A purplish cleavable mass. The specimen was positively identified by Dr. Igor Pekov.

Masutomilite is a mica group member and an Ordinary (True or Common) Mica - Trioctahderal. Contains Li, Al, Mn2+ in the (M) octahedral sites with F>OH in the (A) position. Mindat places K & Rb in the Interlayer sites.

Rare worldwide with only in two in the USA, originally described from Japan. According to Bernard & Hyrsl, occurs in Na-Li rich pegmatites in Czech Republic, and Japan and is typically purple to pink.


Masutomilite

Formula
KLiAlMn2+(Si3Al)O10(F,OH)2 
Crystal System
Monoclinic 
Crystal Habit
Pseudo Hexagonal 
Cleavage
Perfect, None, None 
Luster
Vitreous - Pearly 
Color
purple pink 
Streak
white 
Class
Monoclinic - Prismatic 
Hardness
2.5 
Special Info
XRD Confirmed
Special Info
EDS Confirmed

Montmorillonite

with Quartz - #PD34929
Locality
Newry Mica mine, Oxford Co., Maine, United States 
Formula
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2·nH2
Availability
Sold
Size
8 x 6 x 3.5 cm - Sm Cabinet 

Light pinkish clay mineral. Montmorillonite is a phyllosilicate and member of the smectite group. It is not a mica, and usually not confused as a mica, and is almost always in very fine aggregates. On a microscopic level you may see the basal cleavage confusing it with a mica.


Montmorillonite

Formula
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2·nH2
Crystal System
Monoclinic 
Crystal Habit
Earthy 
Cleavage
Perfect, None, None 
Luster
Earthy (Dull) 
Color
white, gray white, yellow, brownish yellow, greenish yellow 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Earthy 
Hardness
1.5-2 
Collection
Phillips Collection
SOLD
Muscovite - 35305
Muscovite - 35305

Muscovite

var. fuchsite - #35305
Locality
Bahia, Brazil 
Formula
KAl2(Si3Al)O10(OH)2 
Availability
Sold
Size
9.5 x 6 x 2.5 cm - Cabinet 

Emerald green, coarse granular Muscovite with a chromium impurity imparting the rich green color.


Muscovite

Formula
KAl2(Si3Al)O10(OH)2 
Crystal System
Monoclinic 
Crystal Habit
Massive - Lamellar, Foliated, Micaceous 
Cleavage
Perfect, None, None 
Luster
Vitreous (Glassy) 
Color
white, gray, silver white, brownish white, greenish white 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Brittle - Sectile 
Hardness
2-2.5 
Mineralpedia
View Muscovite
On Dakota Matrix
Previously Sold Muscovite
On Dakota Matrix
Other Available Muscovite
WebMineral
View Muscovite
Mindat
View Muscovite

Muscovite

#35313
Locality
Rodinha mine, Jenipapo dist., Itinga, Minas Gerais, Brazil 
Formula
KAl2(Si3Al)O10(OH)2 
Availability
Sold
Size
5 x 3.5 x 3.5 cm - Miniature 

Muscovite mica twinned in stellate habit. The "stars" are 1.5cm across.


Muscovite

Formula
KAl2(Si3Al)O10(OH)2 
Crystal System
Monoclinic 
Crystal Habit
Massive - Lamellar, Foliated, Micaceous 
Cleavage
Perfect, None, None 
Luster
Vitreous (Glassy) 
Color
white, gray, silver white, brownish white, greenish white 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Brittle - Sectile 
Hardness
2-2.5 
Mineralpedia
View Muscovite
On Dakota Matrix
Previously Sold Muscovite
On Dakota Matrix
Other Available Muscovite
WebMineral
View Muscovite
Mindat
View Muscovite

Muscovite

#37782
Locality
Aldeia do Eme mine, Conselheiro Pena, Minas Gerais, Brazil 
Formula
KAl2(Si3Al)O10(OH)2 
Availability
Sold
Size
8 x 4.5 x 4.5 cm - Sm Cabinet 

An excllent cluster of pseudohexagonal crystals to 4.5cm across. 


Muscovite

Formula
KAl2(Si3Al)O10(OH)2 
Crystal System
Monoclinic 
Crystal Habit
Massive - Lamellar, Foliated, Micaceous 
Cleavage
Perfect, None, None 
Luster
Vitreous (Glassy) 
Color
white, gray, silver white, brownish white, greenish white 
Streak
white 
Class
Monoclinic - Prismatic 
Fracture
Brittle - Sectile 
Hardness
2-2.5 
Collection
Art Smith Collection
Mineralpedia
View Muscovite
On Dakota Matrix
Previously Sold Muscovite
On Dakota Matrix
Other Available Muscovite
WebMineral
View Muscovite
Mindat
View Muscovite

All photos by Dakota Matrix and are Copyrighted © and may not be used without permission. Copyright © 2020 - Dakota Matrix Minerals, Inc. Privacy | Terms & Conditions | Site Map