Love the necklace. It must look fabulous when being worn.
Firstly, your stone is a cut stone and not a rough. Rough means how is was when mined. This stone has been manufactured. Manufacted is an industry term for being cut, polished and so on.
In terms of valve, your stone is highly included. In tourmonline, this level of inclusion lowers the value significantly. The “lower” part of the stone is opaque which lowers the value more.
The next question is color. It is a very pretty color and it is right for tourmaline. I cannot say either way if this stone has been color treated from photographs. If it is natural color ,and from the pictures it is possible, it hepls the value. The size also helps the value.
Though not evidence, if the gold is real (look for the stamp) then it is a sign post in the direction of it being a better quality stone than not. Simply, people tend not to spend money on that amount of gold for a worthless stone.
In the industry as well as real life, beauty is in the eye of the beholder. Some people, though not many, would love this stone. I believe they are buyers that would love this stone because of the particular combination of size, color, the many inclusions and the unfinished look to the stone. However, it falls outside what most people look for in tourmaline. It is very likely that a much smaller tourmaline with hgh clarity and a good quality polish and finish would easily be more valuable than this stone.
I hope this was helpful.
Happy New Year,