[Emeraldtarpon]

I agree with TG...it looks like that particular piece has been contaminated somehow.
Maybe its something they used to treat the wood prior to sale and this piece never got rinsed properly? just a guess of course.
Im sure youd be able to exchange it without a problem.

 

[Emeraldtarpon]

The colour is very close to Malachite green (turquoise hue).
Used as...
Antibacterial
Antifungal
Anti parasitic
I wonder if it was treated with this (or Methylene blue)?
It would do all of the above prior to putting it out for sale which makes sense.
Maybe a batch that wasnt washed got through somehow?
Who knows...i could be miles off?