Sweet potato or a yam?

Both sweet potatoes and yams are a daily favorite at our house. One because they are naturally gluten-free, two because of excellent nutritional benefits, and three because they have amazing flavor!

We've never had one like this before! From the outside peal it appears to be a yam, then as I peel the inside shows this hint of orange like a sweet potato. Has anyone seen this?

What should we call it...a sw-am, a y-otato, a sweet-um? Either way it was delicious a cooked up super tasty. ;)