I'm honestly surprised something like this isn't easily found on the internet.
As a rather involved way of getting one of these if you truly can't find one, is to download Unreal Engine 4 (which is free now), and you can export out static meshes from the engine as FBX files. UE4 comes with the following material sphere, that has two material groups:

EDIT: I went ahead and exported out a FBX myself to save you the trouble, if you are still intersted. Send me a private message with your email address and I'll send it to you.