1. The oldest portions of any crystal, which formed first, are found _________. -on the flat surfaces -on the outer edges -where the crystal is most deeply colored -in the center of crystals 2. Which of the following is true about minerals? -Almost all minerals are inorganic. -No mineral is of biological origin. -All minerals are compounds of more than one element. -No mineral consists of more than one type of molecule. 3.Igneous rocks -form from the addition of heat and pressure to a pre-existing rock. -form only at the Earth's surface. -were the first rocks to exist on the Earth. -are coarse-grained if they cool extrusively..