Appendix A - Discrimination of Precious Stones

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	APPENDIX Α.

	On the Discrimination of Precious Stones, Enabling anyone to test the nature of Different Gems.

	HIS Appendix has been prepared with the view of aiding those readers who may wish to become acquainted with some of the scientific means employed in the critical examination of Precious Stones. As information of this kind is necessarily somewhat technical, and must be conveyed in scientific language, it has been considered desirable to add it in the shape of an Appendix rather than to incorporate it in the body of the work. The Hardness of Gems.

	The hardness of a mineral is a physical characteristic of considerable importance as a test, inasmuch as it is found to be fairly constant in each species. In order to give something like quantitative precision to this test, a German mineralogist named Mohs, long ago suggested a standard scale of comparative hardness, which is generally used at the present day by mineralogists. At the head of this scale stands the Diamond, the supreme hardness of which is a character defying imitation. The various degrees of the scale are numerically ranged as follows, tke hardest being placed at the top of the list, with

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