Most often, however, it is a rock
related to granite
(they are called granitoids), and so most often it
contains minerals such as quartz,
and mica such as
other cases, some impressive minerals found in this rock have been
spodumene, tourmaline, beryl, garnet, topaz, and some rare
elements such as tungsten, tin, gallium, rubidium, beryllium
The reason for the large
minerals is that this rock forms in the last
stages of the formation of an intrusion, where water is involved.
makes it possible for the crystals to grow so large because it makes
all the particles very mobile.
While large crystals normally only form
when the cooling is very slow, over millions of years, in pegmatites
they can form much quicker and still grow very large.