Diopside from Indiana County, Pennsylvania, USA
USA | |
| www.nittanymineral.org (2021) https://www.nittanymineral.org/bulletin/NMS1611.pdf |
| [var. Chromium-bearing Diopside] Bikerman, Michael et al. (1997). New Phlogopite K-Ar Dates and the Age of Southwestern Pennsylvania Kimberlite Dikes. |