Chalcedony is a cryptocrystalline form of quartz.
Normally, true blue mineral collectors would not have such specimens in their collection. However, once in a while, a specimen such as this turns up. Its like something out of a cartoon (ever noticed that cartoon characters only have three fingers and a thumb?).
This specimen of chalcedony comes from a cavity in basalt at Springsure in Queensland. Chalcedony was first reported from here in 1887.