Norbergite
Mineral Mg3(SiO4)(F,OH)2
About it
Pale tan to pinkish grains in marble, the magnesium-rich end of the humite group; some from Franklin, New Jersey, glow yellow under shortwave UV.
- Type
- Mineral
- Group
- Silicate (nesosilicate), humite group
- Formula
- Mg3(SiO4)(F,OH)2
- Hardness (Mohs)
- 6–6.5
- Specific gravity
- 3.15–3.18
- Streak
- white
- Lustre
- vitreous (glassy), resinous
- Crystal system
- Orthorhombic
- Colours
- tan, yellow, orange-brown, pink, white
- Transparency
- transparent, translucent
- Cleavage and fracture
- poor; uneven fracture
- Under UV light
- sometimes yellow under shortwave UV
Typical values: real specimens vary. For more, see mindat.org.