(Newbie) Help needed to appraise tourmaline crystals

[kurutoga]

Trying to figure out the value of a few tourmaline crystals. The color is nice but not true blue. Crystals are generally clean but not flawless. Size is around 20-30mm and weight around 5-8 grams. How do you think of $40 per gram?

 

[InToTheMystic]

Is this being asked because you want to get it faceted, or because you want a nice mineral sample?

 

[kurutoga]

Initially I had a few collectors looked at them but they dislike the crystals due to the scratches on the outside.

So I am moving on to faceting. I was told the final stone usually have a yield of 20% in weight. If I consider $100 per carat and labor cost I thought I can only barely make it even - if the crystal costs $40 per gram. Are these reasonable estimates? Apparently the selling price of the stones are related to the color but that color is not entirely pure blue. So I have to discount the selling price. Thanks a lot.