|
USA | |
| (1917) Useful minerals of the United States. Bulletin Vol. 624. US Geological Survey doi:10.3133/b624 |
| (1917) Useful minerals of the United States. Bulletin Vol. 624. US Geological Survey doi:10.3133/b624 |
| (1917) Useful minerals of the United States. Bulletin Vol. 624. US Geological Survey doi:10.3133/b624 |
| JOURNAL OF SEDIMENTARY RESEARCH,VOL. 69, NO.4,JULY, 1999, P. 800–815 |
| Earth Treasures Vol 4, Allan W. Eckert, 1987 |
| Earth Treasures Vol 4, Allan W. Eckert, 1987 |
| Earth Treasures Vol 4, Allan W. Eckert, 1987 |
| American Mineralogist 23:898 |
| (1917) Useful minerals of the United States. Bulletin Vol. 624. US Geological Survey doi:10.3133/b624 |
| (1917) Useful minerals of the United States. Bulletin Vol. 624. US Geological Survey doi:10.3133/b624 |
| www.earthscache.com/louisiana_opal.htm |
| AM. MINERALOGIST, V. 18, 335-340. |