- Barbera Company is a wholesale rock & mineral business located in the San Francisco Bay Area. We have over 20 years of experience serving customers throughout the United States, Canada, and Overseas. We specialize in fine quality Brazilian agate slabs, bookends, and geodes. We have a variety of Amethyst products of all sizes, shapes, and prices. 2000 All Rights Reserved. Barbera Company ...www.barberaco.com