| Marbles-
Recrystalized limestones and dolomites. The texture may range from microscopic
to course, to sugary depending on the extent of recrystalization and metamorphism.
Grade is determined by included accessory minerals. |
| Quartzites
- Compressed and partly to completely recrystalized sandstones. Grain ranges
from course grains cemented with silica to completely recrystalized milky
quartz. |
| Anthracite
(hard) Coal - Compressed and denatured bituminous coal. Water and volitales
are < 10% of the rock. Any fossils originally present have been
destroyed. |
| Contact
and Metasomatic Rocks - Resulting from the reaction of magmatic
or chemically rich fluids with a host rock. they seldom have any clear
structure. Grain size is variable from just visible to fairly large. |
