Gemstones worth investing in will need to be considerably more rare than those found at public dig sites. It may also contain a number of impurities including titanium iron chromium and rutile. Finding gemstones professor hausel s guide to gemstone deposits in nature over the past 30 years hundreds of previously unrecorded gem occurrences were identified in wyoming nearby regions including diamond ruby sapphire pyrope garnet cape ruby cape emerald chromian diopside peridot opal kyanite gold agate jasper iolite others by using geological science geochemistry.