Ingredients of pegmatite

Pegmatites are unusually coarse-grained igneous rocks. They also often contain exotic minerals but even the really common ones are spectacular because of their size. Here you can see four very common minerals that in many cases make up the majority of the rock.

Large crystals of quartz, muscovite, plagioclase, microcline from a pegmatitic rock
The ingredients of a common pegmatitic rock: quartz (W), muscovite mica (N), plagioclase with oligoclase composition (O), and microcline (S). These crystals are large (each one roughly 10 cm across) and they all come from a pegmatite from the same place. Evje, Norway.

Plagioclase and microcline are both feldspars and muscovite is a very common mica. Actually I should have added biotite here as well. This is dark mica which is also often in the mix. The four minerals above were together in one rock and there were no biotite. But few hundred meters away was another quarry that had beautiful biotite flakes as well. So I will add another photo to do justice to iron mica which is rarely missing in a classic pegmatitic rock.

Biotite from pegmatitic granite
Biotite from a granitic pegmatite. Width of sample 11 cm. Evje, Norway.

And here they are all together in one pegmatitic rock. Almost all, muscovite is missing:

Monzogranitic pegmatite
Pegmatite with a monzogranitic composition. Evje, Norway.

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