The Product

Calcite is a Calcium Carbonate (CaCO3) crystalline compound, in several forms and colors.It is named basec on the crystal’s predominant color (Black, Blue, Brown, etc). In some cases, it has layers of different colors and is called Onyx.

They may be observed inside some caves, as stalactites ans stalagmites or having a dogtooth shape (Wich also names these specimens). There are colorless calcite varieties, completely clear and transparent (iceland Spar, because it was first verified on that country), wich constitutes our main product.

Calcite is shaped in several ways. Iceland Spar, for instance, is a romboedric crystalline system employed in prism fabrication and light polarizing lenses. The biggest extraction areas are located in China, Mexico and Brazil, this country being the first one in quantity and quality.

The existing range of shapes and colors is due to the addition of other minerals such as iron, manganese, zinc, magnesium and strontium. Calcite is a typical example of sedimentary mineral (minerals resting immersed in several earth blends, transformed in crystal according to the heat and pressure conditions available).

The main characteristic that separates calcite from other known crystals is its natural capacity of birefringence (a crystal’s property of splitting the refracted ray of light at certain angles of incidence in two, birefraction). The birefringence may be observed when visualizing any object through any good quality crystal: the object has its image duplicated.

Main Uses

Mostly used in the national defense industry, communication equipment and the special optical instrument manufacture. It can be used to determine the distance to an object viewed through it, and was used in the bombsites of world war II bombers. The Calcite Crystal is very suitable material that is used to make the laser-polarized light lens, polarizing prisms. Because of calcite's softness, it should be used in jewelry only where it won't be subject to abuse, and great care should be taken with any calcite specimen.

Curiosities

There are studies and experiments being conducted in order to determine calcite’s therapeutic effects, especially in cases related to bone structures. As calcite is composed by calcium, element also present in the bones, there are individuals that used the mineral to healing bone injuries and even orally to compensate for low calcium levels in the organism.

There are several uses for calcite in our day by day. Besides being used as ornament inside and outside commercial and residential places, it is also used to make polarizing prisms for high definition electronic devices (i.e. Petrologic Microscope), in telecommunications instruments based on fiber optics, as a part of construction cement, in glucose level measurement devices, in fertilizers and correctors. In short: a utilization as diversified as its shapes and colors present in the nature.

Basic Proprieties

Density:
2.710 g/cm3
Mohs Hardness:
3.10

Transparency Range:
350nm – 2300nm, See Transparency Curve

Particle Shape:
Crystalline Rhombihedral

CaCO3 content:
99.94%

Luminousness:
UV³ 72% VL³ 85% IR³ 88%

Hygroscopic Susceptibility:
low susceptibility to moisture
Thermal Expansion

Coefficient:
aa =24.39 x 10-6/K; ac = 5.68 x 10-6/K

Crystal Class:
negative uniaxial with no=na=nb, ne=n Refractive Indices, Birefringence (Dn = ne – no) and Walk-off Angle at 45° (r): 1) no = 1.71425, ne = 1.51140, Dn = -0.20285, r = 6.20° at 0.312 mm 2) no = 1.63457, ne = 1.47744, Dn = -0.15713, r = 6.32° at 1.497 mm Sellmeier Equation(l in mm): 1) no2 = 2.69705 + 0.0192064/(l2 – 0.01820) – 0.0151624l2 2) ne2 = 2.18438 + 0.0087309/(l2 – 0.01018) – 0.0024411l2

Transparency Range:
350nm – 2300nm, See Transparency Curve
Particle Shape:
Crystalline Rhombihedral
CaCO3 content:
99.94%
Density:
2.710 g/cm3
Mohs Hardness:
3.10
Luminousness:
UV³ 72% VL³ 85% IR³ 88%
Hygroscopic Susceptibility:
low susceptibility to moisture
Thermal Expansion Coefficient:
aa =24.39 x 10-6/K; ac = 5.68 x 10-6/K
Crystal Class:
negative uniaxial with no=na=nb, ne=n Refractive Indices, Birefringence (Dn = ne – no) and Walk-off Angle at 45° (r): 1) no = 1.71425, ne = 1.51140, Dn = -0.20285, r = 6.20° at 0.312 mm 2) no = 1.63457, ne = 1.47744, Dn = -0.15713, r = 6.32° at 1.497 mm Sellmeier Equation(l in mm): 1) no2 = 2.69705 + 0.0192064/(l2 – 0.01820) – 0.0151624l2 2) ne2 = 2.18438 + 0.0087309/(l2 – 0.01018) – 0.0024411l2

The Product

Main Uses

Curiosities

Basic Proprieties

Links

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