Name/Title
Calcite / ChalcopyriteEntry/Object ID
2009.62.52Description
Chemical Composition: see above
Crystal System: Hexagonal System
Description: Common Name: Calcite / Chalcopyrite / Chlorargyrite
Chemistry: CaCO3, Calcium Carbonate / CuFeS2, Copper Iron Sulfide / AgCl, Silver Chloride
Group: Carbonites / Sulfides / Halides
Location: Unknown
Description: The calcite crystals are clear with a pale yellow tint, scalenohedron or dogtooth spar shape with random crystals of chalcopyrite ranaging in a varity of iridescent hues on chlorargyrite colored a grayish silver. There are traces of light green malachite around the exposed limenite matrix.
PHYSICAL CHARACTERISTICS OF CALCITE:
Color is extremely variable but generally white or colorless or with light shades of yellow, orange, blue, pink, red, brown, green, black and gray. Occasionally iridescent.
Luster is vitreous to resinous to dull in massive forms.
Transparency: Crystals are transparent to translucent.
Crystal System is trigonal; bar 3 2/m
Crystal Habits are extremely variable with almost any trigonal form possible. Common among calcite crystals are the scalenohedron, rhombohedron, hexagonal prism, and pinacoid. Combinations of these and over three hundred other forms can make a multitude of crystal shapes, but always trigonal or pseudo-hexagonal. Twinning is often seen and results in crystals with blocky chevrons, right angled prisms, heart shapes or dipyramidal shapes. A notch in the middle of a doubly terminated scalenohedron is a sure sign of a twinned crystal. lamellar twinning also seen resulting in striated cleavage surfaces. Pseudomorphs after many minerals are known, but easily identified as calcite. Also massive, fibrous, concretionary, stalactitic, nodular, oolitic, stellate, dendritic, granular, layered, etc. etc.
Cleavage is perfect in three directions, forming rhombohedrons.
Fracture is conchoidal.
Hardness is 3 (only on the basal pinacoidal faces, calcite has a hardness of less than 2.5 and can be scratched by a fingernail).
Specific Gravity is approximately 2.7 (average)
Streak is white.
Other Characteristics: refractive indices of 1.49 and 1.66 causing a significant double refraction effect (when a clear crystal is placed on a single line, two lines can then be observed), effervesces easily with dilute acids and may be fluorescent, phosphorescent, thermoluminescence and triboluminescent.
Associated Minerals are numerous but include these classic associations: Fluorite, quartz, barite, sphalerite, galena, celestite, sulfur, gold, copper, emerald, apatite, biotite, zeolites, several metal sulfides, other carbonates and borates and many other minerals.
Best Field Indicators are crystal habit, reaction to acid, abundance, hardness, double refraction and especially cleavage.
PHYSICAL CHARACTERISTICS OF CHALCOPYRITE:
Color is brassy yellow, tarnishes to irredescent blues, greens, yellows and purples.
Luster is metallic.
Transparency: Crystals are opaque.
Crystal System is tetragonal; bar 4 2m
Crystal Habits are predominantly the disphenoid which is like two opposing wedges and resembles a tetrahedron. Crystals sometines twinned. Also commonly massive, and sometimes botryoidal.
Cleavage is rather poor in one direction.
Fracture is conchoidal and brittle.
Hardness is 3.5-4
Specific Gravity is approximately 4.2 (average for metallic minerals)
Streak is dark green.
Other Characteristics: Some striations on most crystal faces.
Associated Minerals are quartz, fluorite, barite, dolomite, calcite, pentlandite, pyrite and other sulfides.
Best Field Indicators are crystal habit, tarnish, softness and brittleness.
PHYSICAL CHARACTERISTICS OF CHLORARGYRITE:
Color is colorless on fresh surfaces; pearly gray, brown or violet-brown otherwise.
Luster is resinous, silky or adamantine.
Transparency: Crystals are translucent to transparent.
Crystal System is isometric; 4/m bar 3 2/m.
Crystal Habits include very scarce cubes, more commonly massive, stalactitic, crusty and columnar.
Cleavage is absent.
Fracture is conchoidal.
Hardness is 1.5 - 2.5
Specific Gravity is 5.5 - 5.6 (very heavy for translucent minerals)
Streak is white.
Other Characteristics: Crystals darken upon exposure to light and plastic, ductile and sectile, meaning it can be molded, pounded into different shapes and cut into slices.
Associated Minerals include barite, calcite, stephanite, acanthite, native silver and other silver ore minerals.
Best Field Indicators are color, luster, lack of cleavage, density, associations, ductility and crystal habit.
Fracture: conchoidal
Hardness: 3 Calcite
Luster: Vitreous
Occurrence: Calcite occurs as a vein mineral in deposits from hot springs, and it occurs in caverns as stalactites and stalagmites.
Chalcopyrite occurs in a variety of ore types and is most important in copper ore.
Rock Type: Sedimentary
Specific Gravity: 2.7
Streak: white
Variety: Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3).
Chalcopyrite is present in volcanogenic massive sulfide ore deposits and sedimentary exhalative deposits, formed by deposition of copper during hydrothermal circulation. Chalcopyrite is concentrated in this environment via fluid transport.Collection
RAGM Mineral CollectionAcquisition
Accession
2009.62Source or Donor
Museum Collection of MineralsAcquisition Method
DonationDimensions
Height
7 inWidth
5 inLength
7-1/2 inWeight
8.52 ozDimension Notes
Dimension taken at widest pointsLocation
Category
PermanentMoved By
Curtis GardnerDate
May 24, 2023Notes
Added current locationLocation
Container
rightDrawer
2nd shelfShelf
right side, right sideWall
south wallRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Wendy MondryDate
September 19, 2009Location
Container
rightDrawer
2nd shelfShelf
right, rightWall
SouthRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Wendy MondryDate
September 19, 2009Location
Container
RightDrawer
2nd shelfShelf
Right, RightWall
South wallRoom
Delmar Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Wendy MondryDate
September 19, 2009
