Glauconite
Mineral (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
Also called Greensand
About it
Green pellets and grains that colour greensand, formed slowly on the sea floor; common with fossils in marine sands of New Jersey, Kent in England, and New Zealand.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), mica group
- Formula
- (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
- Hardness (Mohs)
- 2
- Specific gravity
- 2.4–2.95
- Lustre
- dull
- Crystal system
- Monoclinic
- Colours
- grass green, yellow-green, blue-green
- Transparency
- translucent, opaque
- Cleavage and fracture
- perfect in one direction (microscopic)
Typical values: real specimens vary. For more, see mindat.org.