There are certainly 100% natural gemstone beads and cabochons available, but there are also many imitations, manmade, dyed, or altered stones as well. Manmade gemstones are beautiful, and a great addition to any piece of jewelry, they just aren't natural. Some gemstones require different or more involved tests than the teeth test to determine whether they are real or fake. These gemstones are called Synthetic, imitation or simulants.  The belief of these natural gemstones having healing powers stems from the idea that energy has been absorbed by the stone for millions of years. Gemstones can help you in increasing your concentration and connecting you with your inner conscious. Gems are characterized in terms of refractive index, dispersion, specific gravity, hardness, cleavage, fracture and luster. They may exhibit pleochroism or double refraction. They may have luminescence and a distinctive absorption spectrum. Material or flaws within a stone may be present as inclusions.