Both basalt rebar and fiberglass rebar are varieties of composite reinforcement. Their manufacturing process is the same; the only difference is raw materials used: the first is basalt fiber based, the second one is glass fiber based reinforcement.
In terms of technical features, the only difference between basalt rebar and GFRP bars is the temperature limit, which a particular material is able to withstand. Fiberglass rebar and mesh does not lose its properties at temperatures up to 200 °C, in case of basalt reinforcement – up to 400 °C.
Therein the second one is much more expensive. Therefore, taking into account the same technical features, basalt plastic reinforcement should be preferred only in cases when the temperature limit of +200 °C is essentially insufficient for your facility.
Moreover, it is believed that the difference between the thermal tolerance of both materials does not matter, since both types of reinforcement are coated with the same composition when producing. Thermal tolerance of this composition is important, not the fiber itself. Therefore, there is no difference between the use of fiberglass and basalt rebar.