Are Granite Crystals Large Or Small. Hmmm granite is intrusive formed and cooled slowly at depth with larger individual crystals. Composed primarily of quartz and feldspar it also may contain orthoclase which is a form of feldspar which can form in plate like layers short prismatic crystals and tabular inclusions. If granite type rock has crystals that grow larger than a large pebble roughly 3 cm or about 1 inch across then it is called a pegmatite.
Granite s wide color range includes mottled grey white pink red black green blue and yellow brown. Figure 2 a sample of rhyolite the crystals are too small to see.
The two rock types have the same chemistry.
This is because any fossils in the original rock will have melted when the rock melted to form magma. Figure 2 a sample of rhyolite the crystals are too small to see. This is because any fossils in the original rock will have melted when the rock melted to form magma. Challenge the students to speculate on the reasons for the obvious difference in crystal size.
