Name/Title
Fluorite / MuscoviteEntry/Object ID
2009.62.68Description
Chemical Composition: see description
Crystal System: Cubic or Isometric S
Description: Common Name: Fluorite / Muscovite
Chemistry: CaF2, Calcium Fluoride / KAl2(AlSi3O10)(F, OH)2, Potassium aluminum silicate hydroxide fluoride
Group: Halides / Mica
Location: Sumayar, Nagor Noth, Pakistan
Description: One large fluorite crystal, translucent white to green, embedded in a thick base of scalloped , layered muscovite on a grainy burnt yellow matrix.
THE PHYSICAL CHARACTERISTICS OF FLUORITE:
Color is extremely variable and many times can be an intense purple, blue, green or yellow; also colorless, reddish orange, pink, white and brown. A single crystal can be multi-colored.
Luster is vitreous.
Transparency: Crystals are transparent to translucent.
Crystal System: Isometric; 4/m bar 3 2/m
Crystal Habits include the typical cube and to a lesser extent, the octahedron as well as combinations of these two and other rarer isometric habits. Always with equant crystals; less common are crusts and botryoidal forms. Twinning also produces penetration twins that look like two cubes grown together.
Cleavage is perfect in 4 directions forming octahedrons.
Fracture is irregular and brittle.
Hardness is 4
Specific Gravity is 3.1+ (average)
Streak is white.
Other Characteristics: Often fluorescent blue or more rarely green, white, red or violet and may be thermoluminescent, phosphorescent and triboluminescent.
Associated Minerals are many and include calcite, quartz, willemite, barite, witherite, apatite, chalcopyrite, galena, sphalerite, pyrite and other sulfides.
Best Field Indicators are crystal habit, color zoning, hardness (harder than calcite, but softer than quartz or apatite), fluorescence and especially the octahedral cleavage.
PHYSICAL CHARACTERISTICS OF MUSCOVITE:
Color is white, silver, yellow, green and brown.
Luster is vitreous to pearly.
Transparency crystals are transparent to translucent.
Crystal System is monoclinic; 2/m
Crystal Habits include tabular crystals with a prominant pinacoid termination. Muscovites four prism faces form diamond shaped "books" and if modified by another pinacoid they form pseudo-hexagonal crystal "books". The sides of the crystal often tend to tapper. Also as lamellar rock forming masses and small flakes in detrital matterial. Twinned crystals can form flat five pointed stars.
Cleavage is perfect in one direction producing thin sheets or flakes.
Fracture is not readily observed due to cleavage but is uneven.
Hardness is 2 - 2.5.
Specific Gravity is approximately 2.8 (average)
Streak is white.
Associated Minerals are quartz, feldspars, beryl and tourmalines.
Other Characteristics: cleavage sheets are flexible and elastic, meaning they can be bent and will flex back to original shape.
Best Field Indicators are crystal habit, cleavage, elastic sheets, color and associations.
Fracture: uneven
Hardness: 4 Flourite
Luster: Vitreous
Occurrence: Fluorite may occur as a vein deposit, especially with metallic minerals, where it often forms a part of the gangue (the worthless "host-rock" in which valuable minerals occur) and may be associated with galena, sphalerite, barite, quartz, and calcite. It is a common mineral in deposits of hydrothermal origin and has been noted as a primary mineral in granites and other igneous rocks and as a common minor constituent of dolostone and limestone.
Muscovite is a common rock forming mineral and is found in igneous, metamorphic and detrital sedimentary rocks.
Rock Type: Sedimentary
Specific Gravity: 3.1
Streak: white
Variety: Fluorite is a widely occurring mineral which is found in large deposits in many areas and comes in a wide variety of colors.
Muscovite is not often valuable as a mineral specimen but sheets of muscovite have a high heat and electrical insulating properties and are used to make many electical components. Muscovite sheets were used for kitchen oven windows before synthetic materials replaced them.Collection
RAGM Mineral CollectionAcquisition
Accession
2009.62Source or Donor
Museum Collection of MineralsAcquisition Method
DonationDimensions
Width
7-3/4 inDepth
3 inLength
6-1/4 inWeight
6.84 ozLocation
Location
Display Case
DS-8Room
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
May 24, 2023Notes
Added current locationLocation
Container
RightDrawer
3rd ShelfShelf
Center, CenterWall
South wallRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Steve MillerDate
January 15, 2010Location
Container
RightCabinet
Case #39Wall
WestRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentLocation
Drawer
far rightShelf
middle 3rd shelf, middle 3rd shelfWall
South wallRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
Permanent
