I believe Hershel is correct- that is is rough untumbled purple Fluorite. I don't have any that beautifully dark in color so was surprised (and jealous!) by your beautiful specimen!
Take a look at the picture here http://www.secretcrystals.net/fluorite-2/ and see if it looks like yours.
Also this link http://www.birdamlasu.com/gemstonesofTurkey.htm will tell you the gemstones found in Turkey, including #41 which is Fluorite.
In Sums, I agree with Hershel :)
Love the rock :)