Ref.: Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 480, 609, 618, 1014.
Veins, 0.4 up to 3.2 meters thick, up to 1 km long, in diabase. Top 10 meters consist mainly of iron sulphates.