NaNa2(Fe2+4Fe3+)Si8O22(OH)2
Arfvedsonite is a generally prismatic black amphibole mineral that usually occurs in alkaline plutonic rocks. It is usually identified through analyses of such rocks and is extremely difficult to distinguish visually from other dark amphiboles.
Selected Australian Occurrences:
- Warrumbungle Volcano, New South Wales.
- Arkaroola, South Australia.
- Woodend, Victoria.
