Man's physical universe

xanabras

MANY VALUABLE MINERALS 187

At some places Epsom salts and gypsum (magnesium and calcium

sulfates) have been formed. At other locations borax and soda have

been deposited. Some of the richest deposits of borax and soda in the

world have been located in the ancient lakes of the Mojave Desert,

which acted as great catch basins for the water from the surrounding

mountains.

Twenty billion tons of valuable potassium salts were formed by the

evaporation of a great inland sea to form the present great Stassfurt

deposits in Germany. Similar deposits have been found far underground

extending for many miles under portions of Oklahoma and Texas.

Another exceedingly valuable product, common salt, is obtained in

some sections of the world today by the evaporation of ocean water or

desert lakes or the water pumped from wells. Salt has been laid down

in huge deposits in many parts of the world by the evaporation of inland

seas. It has been estimated that if the salt in the ocean were separated

by evaporation, there would be an amount sufficient to cover the surface

of the earth to a depth of 112 feet.

Sulfur Is an Important Mineral.

Volcanic activities have produced large deposits of sulfur which

were formed by the cooling or the interaction of volcanic gases. The

action of carbon compounds with gypsum is thought to be responsible

for the huge underground deposits of sulfur in

Precious Stones Are Valuable Because of Their Beauty.

Louisiana and Texas.

During all recorded history man has valued jewels and precious

stones. He has valued them for their beauty and has often endowed

them with imagined powers for good or evil.

Only three minerals possess the requirements, beauty, durability,

and rarity, which characterize precious gems; the precious gems are

diamond, corundum, and beryl. The ruby and sapphire are varieties

of corundum, while the emerald is a variety of beryl.

Beauty is associated with such factors as color, luster, transparency,

and sparkle. The beauty of the diamond is due to the last three of the

above factors, while the beauty of the emerald is due chiefly to its

green color.

All gem stones are sold on the basis of the carat/ which is 200 milligrams

in weight.

A gem is any mineral, precious or otherwise, which has been polished.

When a gem has been cut and mounted in some kind of setting, it is

called a jewel.

1 Do not confuse this term with the carat of gold fineness.

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