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1.—Gems.

Untouched by Acids, giving Fire with Steel; hard, bright.

1.—Diamond.

An Octohædron of unequal Sides, impenetrable, colourles, pellucid.

1. In Shape.

1 . Columnar Diamond.

A Column of fix Angles with two hort Pyramids.

2.—Squared Diamond.

A Column of four Angles, with truncated Ends.

3.—Pebble. Diamond.

Without Angles, rounded or irregular.

2. In Colour.

4 . Red Diamond.

Diamond coloured by Gold:

5.—Yellow Diamond.

Diamond coloured by Lead.

6.—Blue Diamond.

7.—Green Diamonds.

Diamonds, both coloured by Copper.

Variety of Variety.

8.—Purple Diamond.

Diamond coloured by Gold and Copper.