Hope some experts can help me answer the question below~ really need for the help ~~ thanks so much^^

My question:

I am studying a polished cross-sectional piece of an igneous rock under the SEM. How do I determine which phases/compounds crystallize first (from the molten material) from the micrographs taken.

hey, SraJMcGin,anyhow thx for your help. Actually the question from allexpert was me asked their help too~~~

My lecturer still need us further search and get as more as possible different answer~

thx u so much^^