It's a very good alternative to carbon fiber.

It also has one very interesting property that carbon fiber doesn't: it's not conductive. This means, for example, that you can put it in an MRI machine and get signal back. You can't do that with carbon fiber, which shields the return RF signals and gives you a dark image, but doesn't damage anything. Basalt weave composites are basically completely transparent on an MRI.

(For the same reasons, it also can be microwaved successfully. Carbon fiber can not be microwaved. Do not microwave real carbon fiber or carbon fiber composites.)