The term SEA GEM is a combination of two words, PEARL and SEA. A PEARL is a hard, round object that forms inside the shells of certain mollusks, such as oysters, and is often used in jewelry. It is created when an irritant, such as a grain of sand, enters the mollusk's shell and the mollusk secretes a substance to coat the irritant. This substance eventually hardens and forms a PEARL. The SEA is a large body of salt water that covers much of the Earth's surface. It is home to many species of plants and animals, and is also a source of food and resources for humans. Together, the two words form the term SEA GEM, which can refer to any precious gem found in the SEA, such as a PEARL.