A Direct Comparison on a Crystal of Calcite of the X-Ray and Optical Interferometer Methods of Determining Linear Thermal Expansion Evidence of Differences Among Calcite Crystals

Abstract

Measurements by the x-ray and optical interferometer methods on the same specimen of calcite gave values for the coefficient of linear expansion which agree within the limit of measurement. Comparison of these results with data for other crystals of calcite shows that there is a significant difference in the expansion of different crystals. The spacing between the (211) [((100))] planes is also measurably different.