Useful Links:

Mindat

Webmineral - Mineralogy Database

Smorf Crystals - 3D Crystal Models

Rock Pictures:

Arsenopyrite glomerocryst

Arsenopyrite Glomerocryst: Orogenic Au deposit in Victoria, Australia

Arsenopyrite overgrowths over cores of rutile / dendritic pyrite (not pictured). Laser Ablation ICPMS data reveals the cores are heavily enriched in trace elements (inc. Ag, Te, Tl). I'm not 100% on this, but it's possible that the cores formed rapidly due to fluid phase separation (boiling) during ore formation. This process can form dendritic pyrite as well as Te and electrum particles. I'll put up some laser ablation data at some point, but right now I can't be bothered