Classification of Clasitic Rocks.
Grain size is a critical part of clastic rock classification.
The size of these particles determines if the rock is a mudstone or
Sandstone, etc. The size and shape of these grains give us great clues
about the rocks, like where it was deposited. The are a number of charts
that divided grain sizes into groups. The wentworth scale is one such chart.
| Size | Rock Name | Picture |
|---|---|---|
| 2mm | Conglomerate | |
| .0625-2mm | Sandstone | |
| .0625mm | Mudstone |
All Sedimentary rocks are bound together be cement that can be silica based or calcium carbonate based. They can include matrix, which is "mud" that larger clasts float in. So like limestone which is rock formed from Calcium carbonate, clastic rocks can effervesce under hydrochloric acid. Be sure to look closely to see if the clasts are fizzing or the matrix. Geology.com image link