Equipment used to identify gemstones
First and foremost, use your eyes and your brain!
Gemology is a science of elimination. Based on the observation of the various properties of a gem, the possibilities of what it could be are removed until you are left with only one possibility: the correct identification.
Some gems are easily identified with a few simple tests. Who hasn't rubbed a pearl across their teeth to see if it feels rough or smooth? But before doing so, you have already subconciously eliminated all of the other gemstones other than pearl based on the visual observations that you have made: color, shape, luster etc. Of course, the "tooth test" won't tell you if it's cultured or not, or in the case of coloured pearls, if they have been irradiated or dyed.
Most gemstones are considerably less easy to identify. In order to isolate the various properties of a gem, gemology requires some specialized equipment.