A striking specimen of Tabular Calcite Crystals. This is a fine cluster showing one of the less usual formations that calcite appears in. A large 6.2cm Tabular Calcite Crystal dominates the center of this hand sized specimen. The main crystal is surrounded by more than a dozen smaller crystals on a matrix of Galena and some associated sparkling minerals. Aesthetic, collectable and hard to find in nice clean clusters like this. Calcite comes in an incredible range of crystal formations and colours. This specimen will be a great addition to any mineral or crystal collection. Particularly for the collector interested in crystal form and minerals with many variations. This specimen is from very old stock and the best of a bunch.
Mine No. 884 Mine, Chenzhou, Hunan, China.
13.2cm x 11.2cm x 7cm, 590g.
Main crystal, 6.2cm.
Calcite, which gets its name from “chalix” the Greek word for lime, is a most amazing and yet, most common mineral. It is one of the most common minerals on the face of the Earth, comprising about 4% by weight of the Earth’s crust and is formed in many different geological environments. Calcite can form rocks of considerable mass and constitutes a significant part of all three major rock classification types. It forms oolitic, fossiliferous and massive limestones in sedimentary environments and even serves as the cements for many sandstones and shales. Interestingly Limestone becomes marble from the heat and pressure of metamorphic events. The crystals of calcite can form many different shapes. The positive rhombohedron, negative rhombohedron, steeply, moderately and slightly inclined rhombohedrons, various scalahedrons, prism and pinacoid.
Colour is extremely variable but generally white or colourless 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.
Calcite amplifies and energetically cleanses your space. Grounding and bringing a feeling of joy. Balances the emotions, boosts the memory and calms the mind. A good stone for assisting with study. One of the most abundant minerals on Earth and comes in a large range of colours and even crystal habits. Favoured by everyone from kids to serious mineral collectors.
Chakra: Sacral, Solar Plexus & Crown