28 grams untreated Nevada American spiderweb turquoise slice slab vintage gem

A piece from a gem dealer I know.
 
This is the only piece of this material I have as the rest of this gem material was enjoyed for jewellery, this is the end piece of the rock.
 
This turquoise is untreated unstabilised turquoise with top blue colour like the blue skies above Nevada or Arizona.
 
This turquoise is spiderweb turquoise which has a brown matrix that goes through the blue giving a lovely contrast and appearance and there is lots of this matrix.
 
The turquoise on the back, has some glue, this is not treatment, this is from where the chunk of gem was held on to some wood so as to be able to grip the piece while cutting slices of gem off (there is still even some wood flakes), I do show this as I do not want a buyer to be unhappy with their purchase. This wood and glue is easy enough to remove is this gem is to be a bangle or pendant etc however as I am selling this as a gem specimen I will leave it like that for the buyer to choose as now this is provenance as the gem is from the 80s/90s.
 
One image shows a crack, this, again, is untreated unstabilised turquoise as it comes from the ground so if this is for jewellery just facet around that part and used the little part for a ring etc.
 
This gem is 100% guaranteed to not have anty gem treatment.
 
The weight of this gem is 28 grams or 140 carats.