There are many crystals out there and it frequently is confusing as to which are natural and which are 'not'. One tell-tale sign is that if a crystal is too uniform or vivid in colour, or in its pattern, or is perfect in appearance then do be suspicious and double check it is natural with whoever you are purchasing it from.
Here are a list of just some of the crystals that I am aware of that are artificial or treated in some way:
Agates -multi colours
If you ever see a brightly or luridly coloured Agate then it is probably artificial, and unfortunately there is a great deal out there. I personally feel really sorry for the poor crystals that have been dyed in this way. Agates are members of the Quartz family and are favourites to dye because they have striations in them. Different layers of the Agate then absorb dyes in different ways, producing alternating coloured effects.
There are also many other forms of agate which are natural, but they will not look artificial. Some natural coloured Agates are Blue Lace (calming energy), Botswana (grounding and helping to release old addictive patterns), and Moss (gentle and de-stressing).
This crystal does not occur naturally in nature, and is usually quartz (or sometimes Danburite), the surface of which has been coated and bonded with vaporised gold. It is aqua-blue in colour. There are many other crystals with the word ‘aura’ in the name which are similarly artificially created such as ‘Angel Aura’ (coated in platinum and silver), ‘Rainbow Aura’ (gold and titanium) etc.
Citrine has a beautiful uplifting energy. It’s energy is that of joy and abundance. If someone is feeling depressed or not trusting that they will have enough, then this can be a go-to crystal! Amethyst when heated in the earth actually becomes Citrine, so they are the same crystal! However, most Citrine sold on the market is either Amethyst or Smoky Quartz heated artificially to make it more golden. Natural Citrine looks closer to Smoky Quartz. Citrine is the one stone that despite it being heated artificially often, this often doesn’t seem to affect its properties. To me, natural Citrine is more subtle, a little deeper in feel, and not as ‘bright’ as the artificially heated one. Artificially heated Citrine has a more straightforward ‘zingy’, energising, and uplifting feel. However, I have come across many tumbles, geodes (always unnaturally heated Amethyst), and clusters of Citrine that to me have an unpleasant feel, and do not seem happy at all to have undergone this process.
Many years ago I bought this, which at the time I believed to be a genuine crystal (after all it was termed an ‘agate’). It was orange in appearance with a kind of pretty fractured pattern on the surface. I tried and tried to sense its energy but couldn’t get anything, and thought that it was me who had the problem, and I simply wasn’t sensitive enough. Then one day, I suddenly discovered online that it was actually artificial, most likely glass or ceramic in origin. It's pretty but very fake!
Goldstone is artificially created and is a type of glass, usually reddish-brown in colour that has glittery golden ‘stars’ within it (which are usually crystals of copper). It does come in other colours such as blue and green and with other elements inside too to create the sparkly effect. Don't confuse it with Sunstone, which is a natural crystal.
Hematite is not naturally 'magnetic' (though it does give off a very small charge) yet you may find for sale pieces that display powerful magnetic properties. However, this is not actually hematite at all, but instead is a synthetic and artificially created product, which should be labelled as 'Hematine' rather than as Hematite. Natural Hematite is a heavy duty grounding crystal as well as being protective (due to its silvery reflective surface).
This should not be confused with ‘opals’ which are natural minerals. Opalite (also called ‘sea opal’) is a luminescent man-made glass. There is also something called ‘natural opalite’ which is indeed a genuine opal, but green in appearance, so easy to distinguish.
Red Tigers Eye
Gold Tigers Eye and Blue Tigers Eye (also called ‘Hawks Eye’) are both natural and are members of the Quartz family. When Gold Tigers Eye is heated in the earth it becomes Red Tigers Eye. However, natural Red Tigers Eye is very rare and most on the market is therefore heated artificially. Gold Tigers Eye is good for protection on the physical level (great for someone to carry with them if being bullied) whilst Blue Tigers Eye is protective on the subtle levels (psychic attack or if you feel too ‘open’ energetically).
This is often irradiated to make it darker. If it is too dark brown/ black looking and uniform in colour throughout it has probably been treated in this way. Natural smokey is usually lighter, with graduations of colour within. Smokey Quartz is a powerful stone that can help to clear negativity and help us address our fears.
Much tumbled Topaz is natural and comes in golden, clear and icy very slightly blue colours. With a pink hue it is called Imperial Topaz - but this is very rare. For jewellery, If a piece has too deep or striking a colour (too blue for example), then it will have been irradiated. The energy of Topaz is very potent. It has a fast and powerful cleansing energy - I always think of it as like using ‘crystal-bleach’ energetically, so it’s not for the fragile!
Natural turquoise should be at least moderately expensive. Anything cheap is probably not natural. If the colour is too uniform also be very suspicious. The colour and shape of the turquoise should vary throughout a specimen. Howlite, a white crystal, is often dyed and passed off as Turquoise (or called ‘Turquenite’). Another dyed crystal that is masqueraded as Turquoise is Magnesite. Turquoise naturally is also quite brittle, porous and may break easily and so it is often treated in some way - in the past, waxed or oiled and in more recent times, 'stabilised' (possibly coated in a clear, sometimes plastic resin). The best Turquoise comes from the ‘Sleeping Beauty’ mine in Arizona, but this is now very hard to get hold. of. Turquoise has a profound energy. It is a stone that helps someone come from a place of truth, and wisdom and is also highly protective because of its vibration.
Other commonly known crystals that are altered in some way are Lemon Quartz (irradiated and heated), and Crackle Quartz (super-heated, cooled and dyed).