(Heb. gabish, Job 28:18; Gr. margarites, Matthew 7:6; 13:46; Revelation 21:21). The pearl oyster is found in the Persian Gulf and the Red Sea. Its shell is the "mother of pearl," which is of great value for ornamental purposes (1 Timothy 2:9; Revelation 17:4). Each shell contains eight or ten pearls of various sizes.
These dictionary topics are from M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition, published by Thomas Nelson, 1897. Public Domain, copy freely.
Easton, Matthew George. "Entry for 'Pearl'". "Easton's Bible Dictionary".