Opal from Philippine Sea Plate
Japan | |
| (unpublished species lists maintained by local collectors needs confirmation) |
| Mineralogical Journal Vol. 11 (1982) , No. 1 pp1-14 |
Mineralogical Journal Vol. 11 (1982) , No. 1 pp1-14 | |
| Gordon A. MacDonald (1948) Petrography of Iwo Jima. Bulletin of the GSA, 59, 1009-1018. |