Stones, gems or crystals are all minerals that over a period of time have become clear or coloured classifying them into what they are. You might be curious to know what stone you have with you. Here are some ideas to identify the kind of gemstone.
The first step is to examine and see if what you've truly is really a gemstone. Coloured rocks, ores, fossilized wood also look similar and one can get misled by its pretty appearance. If the stone appears sandy or rough then it's definitely not a gemstone. Also gemstones aren't malleable i.e. very easily shaped by hand or hammer and so examine your stone for this. Pearls are not classified under gems.
The most essential check for a gemstone is its hardness. It's not the be all but it does help in classifying the stone. You can get a hardness kit along with the samples of other minerals. You will find a lot of scales for measuring the hardness of stones but probably the most commonly used scale is ?Mohs? scale which rates the stone from one to ten based on its hardness. If the mineral you use scratches the surface of the stone, then the mineral is harder than your stone. By trying various minerals on your stone you can identify the hardness of the stone.
Stones tend to break along particular planes according to their structure. You are able to strike your stone and compare its line with the cleavage chart to identify what stone you've. If feasible chip a small piece of your stone and study its crystalline framework with the assist of a microscope or just use a magnifying glass without having breaking the stone. Every stone has its own distinctive framework of crystals that vary depending on the atomic and molecular framework. Make a mark on a ceramic plate with your gemstone. A lot of stones leave a streak behind and this could be compared to various charts and help further in identification.
There are a lot more tests carried out by experts like the refractive index, specific gravity of the stone, dispersion of light and changes in colour. You could also test the gravity of the stone by placing it in a cup of water. Once you've done all this make a summary and write your conclusion. Examine with an expert if your conclusions are correct.