Ann MacDonald, age 12, of Glendale, Ariz., for her question:

WHERE DO THEY FIND ZIRCONS?

A zircon is a transparent, translucent or opaque mineral that is found in all types of igneous rocks. Sometimes it is found, togetherwith gold, as rounded grains in streams and along sandy beaches. Deposits of gem zircons are found in Sri Lanka, Madagascar, Norway and New South Wales in Australia. No zircons of gem quality are found in the United States.

The chief sources of zircon as an ore of zirconium are Brazil, Australia and, in the United States, Florida and Georgia.

Colorless zircons are known as Matura diamonds or white zircons and they are used as gemstones. Also used as gemstones are zircons of transparent yellow, orange, red and brown varieties. They also occur in shades of green, gray and blue.

The clear or transparent zircons ae known as hyacinth or jacinth. Translucent or opaque varieties and most of the colorless types are known as jargon or jargoon.

When subjected to high temperatures, zircons either change color or lose their color and assume a greater brilliance.