Page:A treatise on diamonds and precious stones including their history Natural and commercial.djvu/121

CHAPTER II.

ON COLORED STONES.

Sect. I.—Oriental Stones^[1], Sapphire, Ruby, Amethyst, and Topaz.

THESE gems are considered to belong to the same class, having the same chemical characters, specific gravity, and hardness, differing only in color.

The perfect Sapphire first claims our attention. When pure, its color is of a clear and

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1. The stones of this class, being superior to all others in hardness and brilliancy, were formerly exclusively called precious. They are all varieties of sapphire—the ruby is sometimes called the Red Sapphire; the oriental topaz, the Yellow Sapphire, &c.