The Ruby
	Rubies and Sapphires are scientifically the same stone, differing only in color. Corundum, the predominating mineral of both, is composed of nearly pure alumina. The coloring substance which differentiates rubies and sapphires is believed to be chromium. In the scale of hardness the gem ranks as No. 9 and is thus the hardest of all substances excepting the diamond. Color is the most important factor in determining the value of the ruby. The gem is always more or less imperfect, but its freedom from bad imperfections is also im­portant. Since fine rubies of all sizes are extremely rare, the price increases very rapidly with an increase in size, and a fine ruby of more than four carats commands an extraordinary price and can be said to be the most valuable of all gems, exceeding greatly a diamond of equal weight. A ruby of eleven carats is reported, some twelve years ago, to have been sold for #80,000, but this is almost the limit of size in which rubies are ever found. The color varies from the lightest