This fossilised Sand Shark tooth necklace has been wire wrapped with sterling silver plated wire with a Opal crystal bead. 
The pendant is on a 925 sterling silver chain.
The species of Shark this tooth belonged to is undetermined but possibly Lemon or Bull shark.
The sharks tooth is 3cm approx on the longest side it's does have some minor imperfections - please see photos for more details. 
The necklace comes in a black jewellery gift box.
Free U.K postage.