To paraphrase Shakespeare, that which we call a gemstone by any other name may not shine as bright. So what is a real gem of a stone.
Numerous names describe a gemstone used in jewelry: natural, laboratory-created or synthetic, simulated or imitation, precious and semi-precious. The natural stone alone possesses the beauty, symmetry, rarity, and value necessary to qualify as a real gem.
A Natural Gemstone
Natural gemstones begin as minerals formed by the earth’s natural processes. Jewelers cut them to show the stones’ best colors and strengths. Minerals form crystals of which seven types of systems exist. For example, garnets are cubic, emeralds are hexagonal, and, peridot and topaz are orthorhombic.
Manufactured synthetic stones, also known as laboratory-grown and laboratory-created, come from the same minerals. They hold the same chemical composition as natural stones. Various techniques grow these crystalline structures. One technique involves a process where powdered chemicals melt, cool, and allow them to crystallize. In another, an ultra-high pressure is put upon the minerals.
Discerning the differences between synthetic and natural stones takes an expert eye. The two types often appear similarly. But, with the use of a hand lens or microscope, internal characteristics reveal the stone’s origin. For instance, with the mineral corundum (from which rubies and sapphires originate), a natural stone has straight growth lines. However, the laboratory-created stone has curved.
Simulated stones, also known as imitation, come from minerals and other substances. They alter the stone to look like a more valuable one. Red tourmaline or red-colored glass simulates a ruby. The differences between simulated and natural stone are more obvious than those between synthetic and natural. Generally, the glass stones show air bubbles and test softer than natural stones.
Historically, imitation stones made of glass go as far back as the Roman era. Known as “paste” because the components of silica, potassium carbonate, borax, lead, and white arsenic mix together to form a wet paste.
Semi-Precious and Precious
Semi-precious and precious are 2,000-year-old terms. Today, professionals prefer other expressions as the distinctions vary and the meanings misinterpreted. For example, amethyst is now considered semi-precious. Recently, chrysoberyl, topaz, and zircon join the list of precious stones. Also, the terms do not necessarily correspond to the value. A high-quality garnet, which is a semi-precious stone, is often ten times the value of a low-quality diamond, which is a precious stone.
The U.S. Federal Trade Commission issues guidelines addressing the misuse of terms describing stones used in jewelry. Any stone that is not a natural gemstone should be conspicuously identified as such, by use of the words “laboratory-grown,” “laboratory-created,” “synthetic,” “imitation” or “simulated.” If it is a real gem, it most likely is a natural stone, as laboratories can rarely replicate the qualities in crystals generated by millions of years of geologic forces.
Note: Earth Systems originally published this article in a newsletter in 2012 written by Margaret Lange and re-edited for the web.