Basalt is stronger than glass fibers (made from silica / quartz / sand), but not as strong as carbon fiber. Also, its more expensive than glass, but less expensive than carbon. Generally considered eco friendly.
Interestingly where carbon fiber's failure mode is instant, failing catastrophically (like say chalk), basalt will be more gradual (like say wood), in some use cases that's an advantage.
Overall though its still not mass produced, uncertain if it will ever reach scale.
If interested in fibers and composites, the YouTube channel Easy Composites is really interesting / educational. For example you can use flax fiber.
Interestingly where carbon fiber's failure mode is instant, failing catastrophically (like say chalk), basalt will be more gradual (like say wood), in some use cases that's an advantage.
Overall though its still not mass produced, uncertain if it will ever reach scale.
If interested in fibers and composites, the YouTube channel Easy Composites is really interesting / educational. For example you can use flax fiber.
https://www.youtube.com/watch?v=AD98L9XlCTU