Crystals..........Fake or Genuine ??

Citrine
Most crystals sold as citrine are heat treated amethyst. When amethyst is heated the purple colour turns to a bright yellow/orange colour. It is possible to find natural citrine on ebay, but the vast majority is heat treated. Of course if one is interested just in colour (from a metaphysical point of view) then this would still be fine.

Photo: natural Citrine

Turquoise
Jewellery made from turquoise is often stabilized (ie treated to make it more durable). Some stabilization techniques affect the crystal structure more than others. A lot of 'turquoise' from China is dyed howlite (so always be careful and check the origin if possible). Again, it is possible to find natural turquoise,- much of which originates in Arizona.

Photo: Natural Turquoise

Agate
Agate is one of the best known examples of colour enhancing. This is a common practice in Brazil. The bright pinks, purples, blues, greens etc are all dyed. This includes agate slices, slabs, bookends, carvings, spheres etc. There are some colourful natural agates though,- blue lace agate, pink moss agate and a few more.

Photo:Natural Blue Lace Agate

Amber
Amber is fossillized tree resin (often containing small insects). Often (again especially from China), artificial resin is impregnated with insects and sold as amber (often with large creatures like scorpions, butterflys etc). Amber can also be melted down and insects inserted in it too. Natural amber can be found though with a little research.

Photo: Natural Amber

Hematite
Most tumbled hematite crystals are natural, but most hematite jewellery is not. Hematite is ground and mixed into a paste like substance and then set into shapes for jewellery. This is why hematite necklaces and other hematite jewellery is so inexpensive (imagine carving the beads by hand).

Photo: Natural Hematite

Other Crystals
Other crystals that are commonly misnamed as natural includes the following. Sunstone (natural) is often confused with goldstone (man-made). Moonstone (natural) is often confused with opalite (man-made). Fibre optic (man-made) is often confused with cat's eye or tiger eye (both natural).
Many other crystals are colour enhanced.