mods... can we have this pinned?
There are a lot of stone out there that are either fake or have been modified by man.
Here's a short list to be going on with but we can add as we go along. I have added links to results of google image searches so you can see them.
Turquiose - most of this is either dyed or reconstituted. It is really really hard to tell the real ones from the fake ones. The only way is to trust who you are buying from.
Amber - most of this is fake, once again it's really hard to tell which is real, although the cheap stuff you see set in jewellery is probably fake. Once again know who you are buying from.
Blue Howlite -
http://tinyurl.com/2uauklk this is howlite dyed blue. I have also seen this in pink and purple.
Brightly coloured agates (pink, blue, purple etc) - These are all dyed
Aqua Aura and other "aura" stones - Aqua Aura
http://tinyurl.com/35tlbez is gold plated quartz. Other brightly coloured "aura" use different metals.
Crackle quartz, rainbow quartz -
http://tinyurl.com/362v7vl These are the brightly coloured stones that have a lot of rainbows in them, these have been heated till they crack then dyed. I'm not talking about the clear ones that have just a couple (
http://tinyurl.com/38oufg5 ).
Citrine - If the citrine is bright yellow it is heat treated amethyst
http://tinyurl.com/3xmgnqb. Natural citirine is generally more dull coloured and even brown
http://tinyurl.com/368ons9
Dark coloured amethyst - if it's not really expensive then this may have been heat treated
Dark smokey quartz - same as the amethyst, unless it is really expensive and the colour not uniform then it is likely to be irradiated.
Goldstone, green and blue goldstone - completely man made
http://tinyurl.com/2vxgj5s
Blue obsidian - some say that this is simply blue glass
http://tinyurl.com/2uqagpoBe sure of your source
Hematite jewellery - the very uniform gunmetal gray stuff
http://tinyurl.com/38l6cb8 ... man made (imho) hematite is often red/gray
http://tinyurl.com/37fo42e
Cats eyes -
http://tinyurl.com/33wuh5b these are the stones that are brightly coloured from one direction and appear to be transleucent in the other... man made, this is a byproduct of the telecommunication industry. It is quartz but it is lab grown and used for fiberoptic cabling. They've just chopped it up and dyed it.
In the end the best thing to do is know who you are buying from. There are few traders out there that aren't trying to rip people off and want people to have real stones rather than just get your money out of you.
In the end it is your choice but do you really want to work with something that isn't natural?
If you know of any more feel free to post up.