The Rock Identification- A Dichotomous Key- Interactive PDF (web version: Rock Key)
The rock cycle diagram
USGS Mineral Resources On-Line Spatial Data Map (select Geology/geologic map, and any other desired data– sample below)
Mineral and Rock Identification Made Easy
North East rock types/examples: http://www.pitt.edu/~cejones/GeoImages/index.html
Splitting
Some rocks split better than others. The quality of splitting is based on the grain or crystalline structure and cleavage planes that should be followed/mimicked when drilling- cleavages are perfect, imperfect, distinct, good, fair, and poor. The difficulty of splitting is formally described as easy, hard, and difficult to produce.
According to Trow and Holden’s Guide to Splitting Stone
Wedges & Shims can generally split stone up to 4-6 times the length of the wedge
Cleavage
| Planes | Type |
| 1 | Basal or pinacoidal |
| 2 | Prismatic |
| 3 at 90 degrees | Cubic |
| 3 not @ 90 degrees | Rhombohedral |
| 4 | Octahedral |
| 6 | Dodecahedral |
