Day 128-Yellow Diamond Optic
Etched Blenko 2010 on the base, yellow was not a catalog color so this is very limited.
UPDATE: July 26, 2012: Here is the word on Yellow. The formula for Yellow has not changed since it was brought back in 2000. The name was changed from Opaline Yellow to just Yellow because most examples did not show the opaline. This same Yellow is used to make the Fire and Ice pieces.