For your crafting pleasure, may I present to you my latest labor of love, a little guide for your spike and stud needs. While this is by no means an official definition, I've found that styles with prongs, iron-on, rivet or nailhead attachments fall under the "stud" category while spikes are usually longer and have a conical shape with screw- or sew-on attachments. Happy making!
Places to buy:
Ebay and Etsy