We always look for quartz rocks. Quartz is a mineral and in its pure form is as clear as glass. But usually, it comes in veins and sometimes outcrops and has a whitish color. Colored forms of quartz like agate, garnet, amethyst and turquoise can be very valuable. We have two fairly large chunks of quartz sitting in front of our house that were retrieved from the desert years ago. This is one of the pieces.