[Krystyna]

   
http://lh3.googleusercontent.com/-FOtfhx...2520cm.jpg
Tonalite pegmatite (white-gray on the right) and Garnet amphibolite (on the left). Black in pegmatite is Biotite, white is plagioclase, gray is Quartz. Trælen, Senja, Norway. Width of sample 10 cm.

https://www.sandatlas.org/biotite/
https://www.thoughtco.com/biotite-geolog...es-4169309