Jasper
Variety SiO2
About it
Opaque, fine-grained quartz full of iron oxides, clay, or other impurities that give strong earthy colours. Found nearly everywhere; it takes a high polish, and patterned kinds carry trade names.
- Type
- Variety
- Group
- Quartz variety (jasper)
- Formula
- SiO2
- Hardness (Mohs)
- 6.5–7
- Specific gravity
- 2.58–2.91
- Streak
- white
- Lustre
- vitreous (glassy), dull
- Crystal system
- Trigonal
- Colours
- red, yellow, brown, green, mixed
- Transparency
- opaque
- Cleavage and fracture
- none; conchoidal to splintery fracture
Typical values: real specimens vary. For more, see mindat.org.