Fluorite on Rose Quartz

Object/Artifact

Crater Rock Museum

One of the most incredible finds of this type.

Name/Title

Fluorite on Rose Quartz

Entry/Object ID

2004.1.3

Description

Chemical Composition: (SiO2) (CaF2) Crystal System: Hexagonal System Description: Common Name: Rose Quartz & Fluorite "QUARTZ" Chemistry: SiO2 , Silicon dioxide Class: Silicates Subclass: Tectosilicates Group: Quartz "FLUORITE" Chemistry: CaF2, Calcium Fluoride Class: Halides Found at Sapucaia Mine, Southeast Region, Brazil. This specimen pink (rosy) quartz crystals with one whitish fluorite crystal sticking out Estimated Value: $42,000 THE PHYSICAL CHARACTERISTICS OF QUARTZ: Color is as variable as the spectrum, but clear quartz is by far the most common color followed by white or cloudy (milky quartz). Purple (Amethyst), pink (Rose Quartz), gray or brown to black (Smoky Quartz) are also common. Cryptocrystalline varieties can be multicolored. Luster is glassy to vitreous as crystals, while cryptocrystalline forms are usually waxy to dull but can be vitreous. Transparency: Crystals are transparent to translucent, cryptocrystalline forms can be translucent or opaque. Crystal System is trigonal; 3 2. Crystal Habits are again widely variable but the most common habit is hexagonal prisms terminated with a six sided pyramid (actually two rhombohedrons). Three of the six sides of the pyramid may dominate causing the pyramid to be or look three sided. Left and right handed crystals are possible and identifiable only if minor trigonal pyramidal faces are present. Druse forms (crystal lined rock with just the pyramids showing) are also common. Massive forms can be just about any type but common forms include botryoidal, globular, stalactitic, crusts of agate such as lining the interior of a geode and many many more. Cleavage is very weak in three directions (rhombohedral). Fracture is conchoidal. Hardness is 7, less in cryptocrystalline forms. Specific Gravity is 2.65 or less if cryptocrystalline. (average) Streak is white. Other Characteristics: Striations on prism faces run perpendicular to C axis, piezoelectric (see tourmaline) and index of refraction is 1.55. Associated Minerals are numerous and varied but here are some of the more classic associations of quartz (although any list of associated minerals of quartz is only a partial list): amazonite a variety of microcline, tourmalines especially elbaite, wolframite, pyrite, rutile, zeolites, fluorite, calcite, gold, muscovite, topaz, beryl, hematite and spodumene. Best Field Indicators are first the fact that it is very common (always assume transparent clear crystals may be quartz), crystal habit, hardness, striations, good conchoidal fracture and lack of good cleavage 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. Fracture: Conchoidal - uneven Hardness: 7 Quartz Luster: Glassy Occurrence: Quartz can occur almost anywhere but the most common occurrence are in hydrothermal veins and druses in chalks, fissures in silicate rocks, layered in sedimentary rocks. 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. Rock Color: Light Rock Type: Sedimentary Specific Gravity: 2.65 - 3.1 Streak: White Texture: Crystalline Variety: -Quartz is the most common mineral on the face of the Earth. It is found in nearly every geological environment and is at least a component of almost every rock type. It frequently is the primary mineral, >98%. It is also the most varied in terms of varieties, colors and forms. This variety comes about because of the abundance and widespread distribution of quartz. and multiple combinations can produce hundreds of unique possibilities. Rose quartz is a type of quartz which exhibits a pale pink to rose red hue. The color is usually considered as due to trace amounts of titanium, iron, or manganese, in the massive material. Some rose quartz contains microscopic rutile needles which produces an asterism in transmitted light. Recent X-ray diffraction studies suggest that the color is due to thin microscopic fibers of possibly dumortierite within the massive quartz.. - 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 covers a wide range only rivaled by quartz.. Fluorite has other qualities besides its great color assortments that make it a popular mineral. It has several different crystal habits that always produce well formed, good, clean crystals. The cube is by far the most recognized habit of fluorite followed by the octahedron which is believed to form at higher temperatures than the cube. Although the cleavage of fluorite can produce an octahedral shape and these cleaved octahedrons are popular in rock shops the world over, the natural (e.g. uncleaved) octahedrons are harder to find.

Collection

Suomynona Mineral Collection, Suomynona Collection

Acquisition

Accession

2004.1

Source or Donor

Suomynona Mineral Collection

Acquisition Method

Donation

Other Name

Rose Quartz & Fluorite

Dimensions

Width

5-3/4 in

Depth

2 in

Length

8 in

Weight

2.6 oz

Dimension Notes

Dimension taken at widest points

Location

Display Case

FS-3

Room

Frieda Smith Hall

Building

Crater Rock Museum

Date

January 5, 2024