This pretty ammonite is quite uneven, so to allow for this I have added an extra row of spirals on the curved side, so that the spirals curl around the stone, rather than sitting flush to it. I have also made the bail circular to mirror the pattern in the ammonite. The whole piece is 2 1/4" tall (including the bail) and 1 1/4" at the widest point. The pendant hangs on an 18" snake chain.
The last picture in the sequence is of the back.
If you would like t make jewellery like this have a look at my Spiral Bezel pendant tutorial.