The stain is not a factor that would determine slipperiness. The stain is usually a part of a larger flooring system that includes a process or a sealer. With polished concrete, the sealer is impregnating they do not test as slippery. Some higher build coatings can be slippery but its best to measure with a Tribometer or even a pendulum test. Real Concrete stains or dyes are not slippery by themselves. Some products sold over the counter labeled as “concrete stain” are not stains but latex coatings(paints) and don’t stain but a coat. These should be categorized as paints.