Aquillian crystal
From Transformers Wiki
Aquillian crystals are a form of intergalactic currency. The Cosmic Carnival accepts them as payment.
Fiction
Marvel The Transformers comics
Berko asked Sky Lynx if he had Aquillian crystals to pay for his and the Spacehikers' admission fees to the Cosmic Carnival. Sky Lynx did not have any, nor any other forms of currency and was thus forced to become an attraction at the Carnival. The Cosmic Carnival
Animated
One of Hubcap's popular scams is to sign his name on a piece of Aquillian crystal, have an accomplice get it into a casino's till, and then con it back. The AllSpark Almanac II