Name/Title
Fluorite/MalachiteEntry/Object ID
78.62.121Description
Chemical Composition: CaF2
Crystal System: Cubic or Isometric S
Description: Common Name: Fluorite
Chemistry: CaF2
Group Name: Halides
Location: Mexico
Description: Delmar described this specimen as a thin piece of mineral, possibly Chert,with
Fluorite and Malachite. Colors: white Chert with orange and yellow stain, small deposits of Malachite on pale grey Fluorite crystals.
PHYSICAL CHARACTERISTICS:
•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.
• Notable Occurrences include in addition to those mentioned above Cumberland, England; Spain; China; Brazil; Morocco; Bancroft, Ontario, Canada; Naica, Chihuahua, Mexico; Germany; Elmwood, Tennessee; Rosiclare, Illinois; Fort Wayne, Indiana; Pugh Quarry and Wood County, Ohio; Nancy Hanks Mine, Colorado and many other USA localities as well as many other localities from around the world.
• Best Field Indicators are crystal habit, color zoning, hardness (harder than calcite, but softer than quartz or apatite), fluorescence and especially the octahedral cleavage.
- See more at: http://www.galleries.com/Fluorite#sthash.eLGfjr0f.dpuf
Fracture: Irregular/ brittle
Grain Size: Medium
Hardness: 4 Fluorite
Luster: Vitreous
Pressure: Moderate
Rock Color: Medium
Rock Origin: Post-depositional
Rock Type: Sedimentary
Specific Gravity: 3.1+
Streak: White
Variety: Fluorite is a mineral with a veritable bouquet of brilliant colors. Fluorite is well known and prized for its glassy luster and rich variety of colors. The range of common colors for fluorite starting from the hallmark color purple, then blue, green, yellow, colorless, brown, pink, black and reddish orange is amazing and is only rivaled in color range by quartz. Intermediate pastels between the previously mentioned colors are also possible. It is easy to see why fluorite earns the reputation as "The Most Colorful Mineral in the World". The many colors of fluorite are truly wonderful. The rich purple color is by far fluorite's most famous and popular color. It easily competes with the beautiful purple of amethyst. Often specimens of fluorite and amethyst with similar shades of purple are used in mineral identification classes to illustrate the folly of using color as the sole means to identify minerals. The blue, green and yellow varieties of fluorite are also deeply colored, popular and attractive. The colorless variety is not as well received as the colored varieties, but their rarity still makes them sought after by collectors. A brown variety found in Ohio and elsewhere has a distinctive iridescence that improves an otherwise poor color for fluorite. The rarer colors of pink, reddish orange (rose) and even black are usually very attractive and in demand. Most specimens of fluorite have a single color, but a significant percentage of fluorites have multiple colors and the colors are arranged in bands or zones that correspond to the shapes of fluorite's crystals. In other words, the typical habit of fluorite is a cube and the color zones are often in cubic arrangement. The effect is similar to phantomed crystals that appear to have crystals within crystals that are of differing colors. A fluorite crystal could have a clear outer zone allowing a cube of purple fluorite to be seen inside. Sometimes the less common habits such as a colored octahedron are seen inside of a colorless cube. One crystal of fluorite could potentially have four or five different color zones or bands. To top it all off, fluorite is frequently fluorescent and, like its - See more at: http://www.galleries.com/Fluorite#sthash.eLGfjr0f.dpufCollection
Delmar Smith Mineral CollectionDimensions
Width
8-1/4 inDepth
1/2 inLength
5 inDimension Notes
Dimension taken at widest pointsLocation
Location
Shelf
CS-E-1Room
Curation StorageBuilding
Crater Rock MuseumCategory
StorageMoved By
CuratorDate
February 23, 2024
