Frogs

The Ruby Contraband was first shown when Dave began an alchemizing session. It was given to him by Future Dave. The item resembles a ruby frog.

Theories and Speculation
Frogs, and other amphibians have been shown to be a reoccuring theme in Homestuck. This includes the Frog Temple found on Jade's Island and the Cherised Idols found on the Land of Wind and Shade. It is therefore likely Dave found this item, along with some amphibians on the Land of Heat and Clockwork.