Name/Title
CalciteEntry/Object ID
78.63.312Description
Chemical Composition: CaCO3
Crystal System: Hexagonal System
Description: Common Name: Calcite
Chemistry: CaCO3
Group: Carbonates
Location: Joplin,Missouri
Description:A crystal mass of calcite from Joplin,Missouri. Colors: Compact crysyal mass in white and cream with small protruding crystals and one large crystal to the side. Some grey and purple metalic ore spots seen at three sites.
Physical Charateristics:
•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.
•Notable Occurrences include Pugh Quarry, Ohio; Rosiclare, Illinois; Franklin, New Jersey; Elmwood, Tennessee; Brush Creek and other Missouri, Wisconsin, Kansas and Oklahoma localities, USA; Andreasburg, Harz Mountains and Saxony, Germany; Brazil; Guanajuato, Mexico; Cornwall, Durham and Lancashire, England; Bombay area of India; Eskifjord, Iceland; many African localities as well as others around the world with their own unique varieties.
•Best Field Indicators are crystal habit, reaction to acid, abundance, hardness, double refraction and especially cleavage.
PHYSICAL CHARACTERISTICS:
•Color is blue-green, green, white, colorless, brown and yellow.
•Luster is vitreous in large crystals to dull in more compact forms.
•Transparency crystals are transparent to translucent.
•Crystal System is orthorhombic; mm2
•Crystal Habits include the bladed crystal form and the botryoidal form as the most common. The crystals are usually elongated and flat. The terminations are different at each end. One termination is blunted by a pedion face that is usually bevelled by several dome faces. The other end is pointed, being capped by a pyramid. The other common form is botryoidal producing a grape bunch texture. Often the botryoidal form has a cock's comb appearance showing rough crystal terminations.
•Cleavage is perfect in one direction.
•Fracture is conchoidal to subconchoidal.
•Hardness is slightly less than 5.
•Specific Gravity is approximately 3.4+ (above average)
•Streak is white.
•Associated Minerals include limonite, aurichalcite, calcite and smithsonite.
•Other Characteristics: strongly pyroelectric and piezoelectric.
•Notable Occurrences include Santa Eulalia and Mapimi, Mexico; New Mexico and New Jersey, USA: England and Zambia.
•Best Field Indicators are crystal habit, color, density and luster.
Fracture: conchoidal
Hardness: 3 Calcite
Luster: Vitreous
Rock Type: Sedimentary
Specific Gravity: 2.7
Streak: whiteCollection
Delmar Smith Mineral CollectionDimensions
Width
4-1/2 inDepth
3 inLength
7 inDimension Notes
Dimension taken at widest pointsLocation
Location
Shelf
CS-D-2Room
Curation StorageBuilding
Crater Rock MuseumCategory
StorageMoved By
Curtis GardnerDate
January 3, 2024Location
Wall
NorthBuilding
Freida Smith HallCategory
PermanentMoved By
Rawley WyattDate
June 3, 2014Location
Cabinet
H-3 frontWall
NorthBuilding
Storage (old gift shop upstairs)Category
Permanent