Clear slate is solid, one color slate, which is all from one “bed” or formation. It is blue-gray to blue black in color. When sealed, oiled or otherwise treated, it is approximately “jet black”. Ribbon slate is formed by Mother Nature when two or more formations were compressed to make one stone from more than two beds. The contrast looks like a ribbon embedded between lighter colored (clear) beds of stone. It is actually more than one bed joined to make one solid stone with ribbon like lines in it. The width of the ribbons varies. Similar to an ornamental dark band, a ribbon may be wide, narrow and sometimes double. When sealer is applied, the ribbon effect is emphasized.