Periclase
Mineral MgO
About it
Rare in nature: glassy grains and small octahedrons in marbles where dolomite was strongly heated, usually altering to brucite at the edges. Known from Monte Somma, Italy, and Crestmore, California.
- Type
- Mineral
- Group
- Oxide, periclase group
- Formula
- MgO
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 3.56–3.68
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Isometric (cubic)
- Colours
- colourless, grey, white, yellow, brownish
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect cubic; uneven fracture
Typical values: real specimens vary. For more, see mindat.org.