Anorthite from
USA | |
| [var. Labradorite] Roberts, Willard Lincoln, Rapp, George Jr. (1965) Mineralogy of the Black Hills. Bulletin 18. South Dakota School of Mines and Technology |
| [var. Bytownite] Roberts, Willard Lincoln, Rapp, George Jr. (1965) Mineralogy of the Black Hills. Bulletin 18. South Dakota School of Mines and Technology |