Zircon semiprecious gemstone index and mineral information

Zircon has been known since ancient times under various names. Zircon’s name most likely derives from the Persian word zargun for (“golden colored”). Zircon was also known in those times as hyacinth. Zircon comes in a variety of colors due to its prismatic to dipyramidal crystals, which can be colorless, yellow, gray, green, brown, blue, and red.

Zircon has had different names in the past: the transparent red variety was called hyacinth (jacinth); clear and colorless zircon from Sri Lanka has been called Matura diamond; and the name “jargon” or “jargon,” derived from the Arabic zargun, has been applied to all other gem colors. Green colored zircon represents the green foliage of the kalpa tree, a gemstone tree that is a symbolic Hindu offering to the gods. It was also believed in the East, that wearing zircon awarded the wearer with wisdom, honor, and riches. Zircon is also considered the gemstone of the month of December.

Zircon is an important accessory mineral in acid igneous rocks. Because of its hardness and resistance to weathering it also can be found in sandstones, especially those bearing gold. When heat treated zircon can change colors. Colorless zircon is rare and when it is cut as a gemstone can easily be confused with diamond, because of its strong brilliance and fire. Zircon crystals are extremely hard, allowing them to survive in many types of rock. They are also resistant to chemical and physical changes. This makes them important in determining how much decay has taken place in other rocks and also estimate the age of the crystal and therefore the age of the rock.

Zircon contains traces of uranium and thorium, both of which are radioactive, and as a result can differ in hardness, specific gravity, refractive index and color. There are two types of zircon. High zircon, which is yellow-brown in color, harder and a much more desirable stone; and low decayed zircon, which is greenish yellow to greenish brown in color, and is softer as a result of radioactive deterioration. Zircon is also useful because it has a high melting point; it is used to make foundry sand, heat-resistant materials and ceramics. Because of its hardness it is also used to make industrial abrasives.

All zircons are brittle and tend to chip at the facet edges. They are classified as: high or normal, which are crystalline; low or metamict, which are amorphous or nearly so; and intermediate, which can be converted by heat to “high.” Zircons are faceted usually in the mixed cut or zircon cut style.

Gemstone quality zircon is found in Ceylon, the Mogok area of Burma, and Thailand. Also well formed red crystals are found in France, brown crystals in Norway, and near-white crystals in Tanzania, some good specimens are also found in Australia and the United States.

Zircon can be confused with aquamarine, chrysoberyl, demantoid, diamond, hessonite, idocrase, sapphire, sinhalite, topaz, and tourmaline.

Mohs’ Hardness: 7.5