looking for chair rail

I am searching for Stone (http://g603.net) chair rail quarried in Mexico that was called "Chocolate TUmbled". It is in 12 inch lengths. We inadvertantly did not get enough to complete the frame on a second mirror in our master bath. Since we purchased it the importer is now receiving a stock that is somewhat smaller in height and (http://maplered.com) depth and (http://maplered.com) it doesn't match. Any suggestions on a source is appreciated