Red jasper is a hard, reddish-brown semiprecious stone often used in jewelry. An opaque form of chalcedony, which is a form of quartz, red jasper has a fine grain and often contains patterns or bands that are formed from minerals or other organic material within the stone. If you need to verify that a piece of jewelry contains red jasper, you will need to carefully assess it to see if it meets all the characteristics of the stone.
Scratch the stone with a knife. Red jasper is a seven on the Mohs hardness scale, so if your stone is truly red jasper, it will not be scratched by the knife.
Look at the stone under a magnifying glass or microscope. Red jasper may contain black streaks or bands of color variations. You might also find minerals within the stone. You will notice a grainy structure because red jasper is formed by tiny quartz crystals.
Hold the stone up to a strong light or the sun. Red jasper is opaque, so you will not see any light shine through. If your stone is translucent, it is not red jasper.
Take your stone to a jewelry store for help in positively identifying your red jasper, especially if you are buying or selling the gem.