I could definitely help explain a lot, but even I am still learning. One thing I am really loving about minerals right now are 2 generations of growth. Over in your neck of the woods there is iridescent calcite from Oskaloosa, Iowa. Really beautiful material, first a dark calcite grew and was coated with dolomite to give it iridescence, then a secondary growth of calcite came in and grew long, white crystals on top of it all to give a wonderful contrast. Here...
Nature is awesome.