Jason Loomer, age 13, of Birmingham, Ala., for his question:

HOW IS EMERY PAPER MADE?

Emery is a grayish black granular variety of Corundum, containing hematite or magnetite, that is used extensively as an abrasive in grinding wheels. Emery paper is made by sifting powdered emery over paper that has been covered with a coating of glue. Emery cloth is made in a similar manner.

Most of the emery used in the United States is imported from Turkey, although it can be found in considerable quantities at Chester, Mass., and at Peekskill, N.Y.

The abrasive is prepared by crushing the emery into a powder. It is then sifted to various degrees of fineness and numbered according to the meshes of the sieves. Because it is very hard (no natural abrasive except diamond exceeds it in hardness), powdered emery is used by lapidaries for cutting and polishing many kinds of stones.

American emery is used as a nonskid element in pavements and stairways. Turkish emery is used principally for abrasive paper and cloth.