Are all clear Tequila's Blanco's?

No! A cristalino tequila is essentially any aged tequila, reposado, añejo, or extra añejo tequila that has been filtered (often through charcoal) to remove the naturally occurring colors it picks up from spending time inside the barrel. The filtration process strips the color and some of the tequila’s woodier notes without removing the rich flavors and textures imparted by the barrel. The result is a tequila that possesses the complexity and character of an añejo, complemented by the crisp, bright notes of a blanco. Cristalino has not been officially recognized as a distinct category of tequila yet. Still, many distributors have started producing cristalinos, and I expect that, over time, this will become a recognized category.