World Book Trivia Quiz For Kids--11/26-gemstones

Most gems are minerals, materials that come from the earth. But some gems come from plants or animals. For example, pearls are formed in the shells of oysters. Amber comes from ancient pine trees. Coral comes from the skeletons of tiny sea animals.

A birthstone is a jewel that is special to a month of the year. It is supposed to bring good luck to anyone born that month. November's birthstone is topaz.

A diamond is the hardest natural material in the world. It is also one of the most valuable natural materials.

Gems sparkle because they bend light rays. Some gems bend light more than others. The more a gem bends light rays, the more it sparkles. Diamonds are some of the most brilliant, sparkling gems.

The size of a diamond is measured by its weight in carats. One carat equals 200 milligrams. The biggest diamond ever found was called the Cullinan. It was found in 1905 in South Africa. It weighed 3,106 carats, or about 1 1/3 pounds (0.6 kilogram). It was cut into 9 large gems and 96 smaller stones.

Jade is a valuable stone with beautiful colors. It is known for its strength and hardness. The Chinese have used jade for fine carvings and jewelry for more than 3,000 years.

The value of an emerald depends on its color and its lack of flaws, or defects. An emerald with a bluish color is worth more than one with a yellowish color. Most emeralds have tiny flaws.

An oyster is a sea animal with a soft body inside a hard, two-piece shell. Some kinds of oysters can make a beautiful gem called a pearl. Oysters live along coasts in areas with mild water. People catch and eat millions of oysters every year.

Natural gems can be very expensive. Scientists have learned to make rubies, emeralds, and sapphires in laboratories.

Sapphires are hard, clear gems, or jewel stones. They are a kind of mineral known as corundum. The red kind of corundum is called a ruby