One type of Tanzanite that people have asked about is Ocean Tanzanite. This is not some special type of Tanzanite, it's just a name given to this color of Tanzanite from JTV (also known as Jewelry Television), with their trademark. In the past JTV called the stone/color just green Tanzanite as it was similiar to Tsavorite Garnet, but it probably didn't sell enough, so they coined the term "Ocean Tanzanite" to be more marketing savvy.
Tanzanite from Tanzanite Jewelry
You can find Green Tanzanite and even Pink Tanzanite out there, but according to JTV, it's all ocean Tanzanite.
Here at Tanzanite Jewelry Designs, we recommend not going by names, but by the actual color of the gemstones. If you see our collection of Tanzanite, you will find the darkest blues and purples, but we still just called them Tanzanite.
If you ever have any questions about Tanzanite or the colors available for Tanzanite, please call us at 1-800-348-4499.