I know this rock, or at least its metamorphasis into the colors that are displayed. I also have one like it. The red through yellow colors are the result of either arsenopyrite, ruby silver (silver antimony arsinide) or sperrylite (platinum arsinide). Not much value as a mineral specimen if it is just arsenopyrite but the other two are very pricey.
Test for silver by roasting then reducing a piece of the metalic crystal on charcoal. If ruby silver it will leave a silver ball. If platinum group then it will leave a silver-grey poreous crust. If arsenopyrite perhaps a white powder, 'tho arsenic is quite volatile so you will probably blow most away with the torch. Do this outside and use a small piece. Arsenic is a poison; smells like garlic.
Sperrylite ore is very heavy. If it contains sperrylite then the specific gravity should be over 7.
There are other tests but the low melting point of silver and the unmeltability of platinum with a propane torch should suffice.
A big clue is the geology in which it was found. If in ultramafics (dark, basic, deep seated mantle rock, usually not surface flow like basalt or felsite) such as the Sudbury or Manitoba nickel belts then it is probably sperrylite. Also could be sperrylite if found in pegmatite, serpentine or olivine-rich rock. 99% sure it's arsenopyrite if found in scarn or carbonate rock.
Dusty Roads (40+ years a Canadian Prospector)