Dacite
Rock
About it
Light grey volcanic rock between andesite and rhyolite, often with glassy quartz and white feldspar crystals in a fine groundmass. Builds lava domes like the one in the crater of Mount St. Helens; named for Dacia, now Romania.
- Type
- Rock (igneous)
- Group
- Igneous (volcanic)
- Specific gravity
- 2.35–2.8
- Lustre
- dull
- Colours
- light grey, grey, pinkish grey, light brown
- Transparency
- opaque
Typical values: real specimens vary. For more, see mindat.org.