| Transmission Range | 0.3 to 2.3 μm |
| Refractive Index | No 1.6654 at 0.51 μm |
| Reflection Loss | 11.7% at 0.51 μm (2 surfaces) |
| Absorption Coefficient | n/a |
| Reststrahlen Peak | n/a |
| dn/dT | 3 (para) 13 (perp) x 10-6 K-1 at 0.5 micron |
| dn/dμ = 0 | n/a |
| Density | 2.71 g/cc |
| Melting Point | 825°C (Decomposes) |
| Thermal Conductivity | 5.526 (para) 4.646 (perp) W m-1 K-1 at 273K |
| Thermal Expansion | 25 (para) -5.8 (perp) x 10-6 K-1 at 273K (2)(3) |
| Hardness | Knoop 155 Moh 3 |
| Specific Heat Capacity | 852 J Kg-1 K-1 |
| Dielectric Constant | 8 (para) 8.5 (perp) at 10kHz at 293K |
| Youngs Modulus (E) | 72.35 (perp) 88.19 (para) GPa |
| Shear Modulus (G) | 35 GPa |
| Bulk Modulus (K) | 129.53 GPa |
| Elastic Coefficients | C11=137; C12=45; C13=45; C14=21; C33=79 |
| Apparent Elastic Limit | 4.83 MPa (700 psi) |
| Poisson Ratio | n/a |
| Solubility | 0.0014g/100g water at 25°C |
| Molecular Weight | 100.09 |
| Class/Structure | Trigonal (hex), R3c, {10-14} cleavage (1) also see Product Notes |
| μm | No | Ne | μm | No | Ne | μm | No | Ne |
|---|---|---|---|---|---|---|---|---|
| 0.20 | 1.9028 | 1.5765 | 0.64 | 1.6550 | 1.4849 | 1.04 | 1.6428 | 1.4799 |
| 0.30 | 1.7196 | 1.5137 | 0.71 | 1.6521 | 1.4835 | 1.50 | 1.6346 | 1.4774 |
| 0.41 | 1.6801 | 1.4954 | 0.80 | 1.6487 | 1.4822 | 1.91 | 1.6270 | 1.4757 |
| 0.51 | 1.6653 | 1.4896 | 0.91 | 1.6458 | 1.4810 | 2.10 | 1.6220 | 1.4749 |
Calcite is often mined naturally. Crystran Ltd has a stock of small calcite “rhombs” of good clear optical quality. Calcite cuts and polishes well.
CLEAVEAGE PLANE :
There can be confusion in the definition of the cleavage plane in calcite. Conventionally this has always been referred to as {10-11} but recent papers on AFM studies use {10-14}. Calcite cleaves between the bonds of the CO3 groups (in the CO3 layer). The CO3 group are offset relative to each other and inclined to the c axis giving 3 cleavage directions defining a rhomb. Following the {10-11} nomenclature the unit cell requires ¼ the length of the c axis as measured from XRD (on a dimension 4 times longer). The correct Miller indices are {10-14} but the conventional {10-11} is often used in order not to confuse and for easier comparison. (1)
REFERENCES:
1. Private Communication. J.A.Elliott. Dept. Materials Science, University of Cambridge. 2011
2. Crystallography – LINK to: Practical Crystal Measurement. A.E.H.Tutton, Vol2, page 1329
3. Linear Thermal Expansion of Calcite – Link to: Mineral Society of America, Linear Thermal Expansion of Calcite.
WEBLINKS:
http://webmineral.com/data/Calcite.shtml – Has further information regarding Calcite.