BrickLink maintains a Color Guide that shows our recognized colors. Color titles do not always match the LEGO Group's titles and BrickLink does not separate all existing colors. Only items in the Parts and Gear item types can be assigned colors.
Known colors for a part or gear are based on inventory inclusions and will not appear unless the item exists in an inventory. The system will recognize up to 10 levels of inventory inclusions (for example, a subpart that appears in a part that appears in a figure that appears in gear included in a set). Known colors for catalog entries are based on real-time data. Known colors for other pages and features are cached and updated once daily.
Gear should only be assigned colors when the item is a solid color or one predominant color and the item exists in multiple colors within the same catalog entry.