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USA | |
| Mineralogy of Pennsylvania-1922 Samuel S. Gordon, pg. 174 |
| Mineralogy of Pennsylvania-1922 Samuel S. Gordon, pg. 181 |
| Gordon, S.G. (1922) The Mineralogy of Pennsylvania. 255 pp., Philadelphia. |
| Joe Dunleavy (Pers. Comm.) |
| Gordon's Mineralogy of Pennsylvania (1922) p. 191 |
| Gordon, S.G. (1922) The Mineralogy of Pennsylvania. Special Publication No.1, The Academy of Natural Sciences of Philadelphia, 255 pages, at p.191. |
| Lapham & Geyer, 1965. Mineral Collecting in Pennsylvania |
| Personally Collected 4/12/2008, Mark J. Sigouin, Pennsylvania Licenced Professional Geologist |
| Lapham & Geyer, 1965. Mineral Collecting in Pennsylvania |
| Gordon, Mineralogy of Pennsyvania, 1922 - p. 224 |
| Gordon: Min. Penn (1922) p. 230 |
| Gordon, 1922. The Mineralogy of Pennsylvania |
Brinton's Quarry, Westtown Township, Chester County, Pennsylvania, USA