Zircon
Mineral ZrSiO4
Also called Hyacinth, Jacinth, Jargon, and Starlite
About it
Square prisms capped with pyramids, heavy and with a near-diamond lustre; Bancroft, Ontario, and Sri Lanka are classic. Grains from Australia's Jack Hills are the oldest known minerals on Earth.
- Type
- Mineral
- Group
- Silicate (nesosilicate), zircon group
- Formula
- ZrSiO4
- Hardness (Mohs)
- 7.5
- Specific gravity
- 3.9–4.7
- Streak
- white
- Lustre
- adamantine (diamond-like), vitreous (glassy), greasy
- Crystal system
- Tetragonal
- Colours
- brown, red-brown, yellow, colourless, blue, green, grey
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- indistinct; conchoidal fracture
- Under UV light
- often yellow or orange under shortwave UV
Typical values: real specimens vary. For more, see mindat.org.