There are two major slate quarries at Rosebush: Bellstone Quarry and Rosebush Quarry, on the western slope of a spur to the south-west of Foelcwmcerwyn; immediately north of Rosebush village. The Bellstone Quarry to the north and the Rosebush quarry to the south, each originally had their own dressing floors and tramway systems. Within each quarry there are two major working areas, and a number of small trials; and each of the major workings exhibits a different stage of development.
Of the two quarries, Bellstone was the first to be opened up. Originally known as the Prescelly Quarry it was first worked in December 1825. By 1840 it had expanded to such an extent that it was necessary to divert the track, running north below the quarries to Bwlch Pennant, which was being overrun by the spoilheaps. Working continued intermittently to the 1860s when the name Bellstone was first used, and on a more intensive level through the 1870s and 80s when it had the benefit of the railway built to serve the Rosebush Quarry. The last company to work Bellstone was dissolved in 1891.