The particular name of an igneous rocks consisting of minerals is best determined using the chart in the lab book and noting:___
_. (a) the presence of quartz and one other mineral.
(b) the presence of vesicles (gas pockets) in proportion with the presence of the mineral quartz.
(c) the relative color (light, intermediate, or dark) and the relative size of the minerals (phaneritic/aphanitic).
(d) whether the minerals present are metallic or non-metallic and then determining the streak on each mineral present.
Color indicates the composition of a rock or mineral. A felsic composition is indicated by light colors such as white or pink. Intermediate rocks or minerals have a medium color such as gray or an equal part of dark and light colored minerals . Mafic or ultramafic rocks or minerals are dark colored such as black or brown however they might also contain light colored minerals within them.
we need tropical rain forests because they produce oxygen and clean the atmosphere to help us breathe. They also provide us with medicinal plants and may be the source to cure deadly diseases.
