Name/Title
CalciteEntry/Object ID
2004.1.157Description
Chemical Composition: Zn4 Si2 O7 (OH)2 -H2O
Crystal System: Orthorhombic System
Description: Common Name: Calcite
Group Name:
Chemistry: CaCO3, Calcium Carbonate
Location:India
Description: A large sheet with two distinct sides. One side is covered with reddish tan crystals on a reddish brown drusy base. The other side is smaller, clear crystals on a drusy coated stalagmite looking base that is a greyish color.
PHYSICAL CHARACTERISTICS:
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.
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 are crystal habit, reaction to acid, abundance, hardness, double refraction and especially cleavage.
Fracture: conchoidal
Hardness: 5 Apatite
Luster: Vitreous
Occurrence: 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.
Specific Gravity: 3.4
Streak: White
Variety: Possibly the most well known of calcite's varieties is its most common form, the classic scalenohedron or "Dogtooth Spar"Collection
Suomynona Mineral Collection, Suomynona CollectionAcquisition
Accession
2004.1Source or Donor
Suomynona Mineral CollectionAcquisition Method
DonationDimensions
Width
13 inDepth
6 inLength
21-1/2 inDimension Notes
Dimension taken at widest points
