One store owner here in Arizona calls jet a gemstone but I’m almost sure that isn’t correct – can you tell me if I am right or not?
Good question ! Here’s my official answer.
Jet also known as Acoma Jet
Jet is an organic fossil – a solid, durable type of lignite coal that originated from wood.
The term coal means the fossilized remains of ancient organic matter that ranges from bog materials to peat to wood. Jet, however, is the fossilized remains of araucaria (coniferous evergreen) wood specifically.
Therefore jet is not a stone or a mineral. It is fossilized wood.
You’d think jet is black……as in jet black……but actually it is very very dark brown but it appears black.
It is mined around the Acoma Pueblo region of New Mexico, among other places, thus the name Acoma Jet, or Jet for short.
It can be highly polished. Therefore, it is very popular for carving fetishes. Here are some examples of Zuni Fetish carvings from jet.