jacinth

Jacinth is a gemstone name historically used for a fiery orange to reddish-orange variety of zircon. In older texts the term is often synonymous with hyacinth. The stone was highly prized in antique jewelry for its bright color and lively sparkle.

The name comes from Latin jacinthus, from Greek hyakinthos, linked to the hyacinth flower. Jacinth appears in ancient gem lists and in Bible translations as a key precious stone, though its exact historical identity has varied among sources.

Modern usage: In contemporary gemology the term jacinth is largely historical; the color range and the common name refer to orange zircon varieties. Today most stones called jacinth are described simply as zircon, orange zircon, or hyacinth zircon.

Properties: Jacinth refers to zircon with a color range from orange to red-orange. Zircon (ZrSiO4) has a hardness of 7.5 on the Mohs scale and is known for its relatively high refractive index and dispersion, producing noticeable fire when cut well. Zircon crystals are typically tetragonal and can exhibit strong brilliance in faceted forms.

Occurrence and sources: Orange zircons have been found in Sri Lanka, Madagascar, Australia, Tanzania, and other localities. They form in igneous and metamorphic rocks and are mined from pegmatites and alluvial deposits.

Care and identification: Jacinth/zircon should be distinguished from similarly colored stones such as garnet and topaz by gemological testing, including refractive index and birefringence. Heat treatment is less common and can alter color.