Here are some possibilities, depending on the specific combination of blue and red:
* Jasper: Jasper is a variety of chalcedony that can come in a wide range of colors, including red, brown, yellow, and blue. Some jaspers have a combination of red and blue, often with swirls or bands.
* Agate: Agate is another variety of chalcedony, known for its banded patterns. Some agates have blue and red banding, creating a visually striking effect.
* Rhyolite: Rhyolite is an igneous rock that can be red, pink, or even blue, depending on the minerals present.
* Quartzite: Quartzite is a metamorphic rock formed from sandstone. Depending on the impurities present, quartzite can have red, blue, or even green hues.
To give you a more accurate answer, I would need more information about the rock, such as:
* Where did you find it? Location can help identify the type of rock.
* What is the texture? Is it smooth, rough, or layered?
* How hard is it? Can you scratch it with a fingernail or a coin?
If you can provide more information, I might be able to give you a better idea of what kind of rock you have.