How much should I sell a tiny quartz crystal on okorder?
There are different types of feldspar, all of which will contain some Aluminum, some Silicon, and a bunch of Oxygen atoms. Sometimes the AlSiO is bonded with K (potassium-feldspars), sometimes with Na, and sometimes with Ca --- there are different forms of all of these... But the important elements that will make up a feldspar are K, Al, Si, and O, or Na, Al, Si, and O, or Ca, Al, Si, and O. Pure quartz is made up of Si and O - different impurities create many different kinds of quartz. Mica is like feldspar in that it comes in many different forms. O is always present in micas, and Si is usually present, but otherwise you have a long list of different elements that can make up the rest of the mineral. Common forms of mica include Muscovite and Biotite. Since I don't know the exact chemical composition of these I'll link the wikipedia section on those two minerals.
Basically all the three minerals will have different proportions of silicate(SiO2) compounds. Quartz is pure sio2 Feldspar could contain a range of elements in K to Ca series along with sio2 Mica could contain a range of elements ranging from K,Ca, Fe, Mg along with sio2
