Danalite
Mineral Fe4Be3(SiO4)3S
About it
The iron member of the helvine group, in pink to reddish-brown octahedra and grains in granite and skarn; named for James Dwight Dana, with type material from Rockport, Massachusetts.
- Type
- Mineral
- Group
- Silicate (tectosilicate), sodalite group
- Formula
- Fe4Be3(SiO4)3S
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 3.28–3.46
- Streak
- white
- Lustre
- vitreous (glassy), greasy
- Crystal system
- Isometric (cubic)
- Colours
- yellow, pink, reddish brown, red
- Transparency
- transparent, translucent
- Cleavage and fracture
- poor octahedral; uneven to conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.