One of the most common forgeries I have come across is that of misidentified Turquoise. True Turquoise colors include a bright blue, sky-blue, pale green, blue-green, turquoise-blue, apple green, green-gray. Many may have streaks of pale greenish blue to white.
Watch carefully for the wording a vendor uses. For instance Turquentine is the name given to Howlite or Magnesite that has been dyed. Turquenite is made from Howlite or Magnesite crushed to powder, with blue dye and resin added then compacted and polished.
In a batch of stones I recently purchased, with Turquoise being one of the pieces listed in the batch, I was dismayed to find that it was not Turquoise at all. Instead, it was dyed Howlite. This was easy to see as the streaks were most decidedly gray to black, not greenish blue to white.
Another example of false Turquoise was at a gem fair I attended. I purchased several pendants from a vendor at the show. He correctly identified the pieces as I picked them up until it came to the Turquoise ones. He called it Turquoise due to the pendant being a Turquoise color, but it was most decidedly NOT Turquoise. The color was not even, it had patches of white and silvery/gold. When I pointed this out to him, he changed his mind and said it was a denim Lapis Lazuli. Curious, I purchased one. My fool proof test of this piece would tell me what it REALLY was.
Upon returning home, I wrapped the piece in a towel and tapped it with a hammer. Yes, you guessed it!! It was obviously Howlite/Magnesite that had been dyed. You could even see where the dye job had started to bleed in. It looked more like an M & M with its candy coated outer shell!
Often it CAN be Turquoise which has gone through the stabilization process (the turquoise is powdered and a stabilization agent added to it to “firm it up” so to speak, making it less fragile). The color and the veining can be a real indicator.
This is where education is your friend. For instance, if you see a piece in which the color has unnatural splotches or is too evenly distributed and you may suspect it is a fraud, simply ask more questions. Point out the color distribution and point blank ask f it is dyed or enhanced. As always, just be discerning. Ask a lot of questions. In the end, your intuition will be your guide.
Image from thevug.com