High Quality Content by WIKIPEDIA articles! Using the same 3D optical data storage technology as the fluorescent multilayer disc, the fluorescent multilayer card was a memory device proposed by Consallation3D. It consisted of a card containing a square shaped clear part with multiple layers each containing a different fluorescent material capable of emitting light at a different wavelength from the other layers. By this approach, the device could contain several layers, each with individually addressable data. It was suggested that a card with the data area roughly 25 mm (one inch) wide could be able to hold 10 GB of data.