The quality of the Keystone varies depending on the land where it is excavated. Some areas of Florida Keystone have large sections of fossilized Brain Coral, and other sections are composed of smaller shells and fossilized plants. Florida Keystone has various textures. depending on the shells it is composed of. Larry's Cap Rock & Stone initially cuts the keystone into blocks, and transports it to our fabrication facility, where it is cut to the customer's specifications. Material is typically white in color.