A Geoscience Digital Image Library
A Geoscience Digital Image Library
| Title | Rhyolite, Castle Rock, Douglas County, Colorado |
|---|---|
| Description | This somewhat vesicular pyroclastic rock is a pinkish specimen with scattered phenocrysts of glassy quartz in a quartz-feldspar matrix. Although hard to see in hand specimen, the sample also contains euhedral sanidine tablets, biotite euhedra, subhedral to euhedral sodic plagioclase laths, a few magnetite crystals, and angular quartz pieces. The tan-brownish matrix consists of devitrified glass shards and cryptocrystalline dust. |
| Chronostratigraphy | Tertiary (Eocene) |
| Location | USA ▹ Colorado ▹ Douglas. Near Denver. Castle Rock. |
| Photographer | Joseph Hartman. 2001-02-13. |
| Collection | Ward’s Collection of Classic North American Rocks #11. |
| Key words | rhyolite, Colorado |
| Tech details | 814 KB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60mm AF Nikon micro lens. |
| GeoDIL number | 52 |
 | |