Colour
The colour is one of the 6 charateristics. it is one that can be very unquie. Since colur is one of the most attrcive things to us humans. Colour is also a way to identifying it allthough it doesn't all ways work like gold and pyrite.
Gold
http://www.consrv.ca.gov/cgs/information/PublishingImages/GoldNug01.jpg
Gold
http://www.consrv.ca.gov/cgs/information/PublishingImages/GoldNug01.jpg
Pyrite
http://www.minerals.net/MineralImages/pyrite2.jpg
http://www.minerals.net/MineralImages/pyrite2.jpg