It's generally not very easy in some cases to identify the fake ones,at least it isn't if you're not sure you can easily feel the energy in real crystals. You generally won't find uncut and unprocessed fake crystals,the fake ones are the ones they sell for jewellery. Try to buy crystals from a certain shop that you trust, so that you will have some definitely real crystals to compare them the ones of the same kind you are looking into buying(for example if you intent to buy pink quartz crystals study the one you already have,so that you'll feel that something is off with the ones you intent to buy if they're fake). Also look online,there are web pages that explain what are the differences between real and fake crystals of different kind,so you can check specifically the ones you are looking into. With experience it will be easier to recognise the real crystals.
Also beware of big quartz crystals,the ones that are a stone cut in half with the quartz inside. The sell them in bright colours, but the colours are not real,they just dye the crystals to make them look spectacular.Only a few of them are actually something more than pure crystal quartz(although you can find some good stones like that with amethyst inside instead of crystal quartz).
Merry meet and merry part and merry meet again.