RefractiveIndex.INFO

Optical constants of CRYSTRAN - Optical materials
CaCO₃ - Calcite (o)

Complex refractive index (n+ik)[ i ]

Derived optical constants

Conditions

direction: o

Comments

Calcite, or Iceland Spar, is a strongly birefringent material and is used for polarisers and retardation plates. 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.

Optical data are for ordinary ray (o).

References

Crystran Ltd. The Crystran handbook of infra-red and ultra-violet optical materials (5th edition, 2023)
See also Crystran CaCO₃ online data sheet

Data

[CSV - comma separated]   [TXT - tab separated]   [Full database record]

Optical transmission calculator

Sample transmittance and reflectance

Fresnel reflection calculator

Reflectance[ i ]

Reflection phase[ i ]

Brewster's angle[ i ]

Additional information

Properties of CaCO₃ - Calcite (o)

density:
  - 
    value: 2710
thermal_dispersion:
  - 
    type: constant
    wavelength: 0.5
    direction: para
    value: 3.0E-6
  - 
    type: constant
    wavelength: 0.5
    direction: perp
    value: 1.3E-5
thermal_expansion:
  - 
    temperature: 273
    direction: para
    value: 2.5E-5
  - 
    temperature: 273
    direction: perp
    value: -5.8E-6
hardness:
  - 
    type: Knoop
    value: 1520000000
  - 
    type: Mohs
    value: 3
melting_point:
  - 
    value: 1098
thermal_conductivity:
  - 
    temperature: 273
    direction: para
    value: 5.526
  - 
    temperature: 273
    direction: perp
    value: 5.526
youngs_modulus:
  - 
    direction: para
    value: 88190000000
  - 
    direction: perp
    value: 72350000000
solubility:
  - 
    value: 0.014