Instructions
Inspect the angles on the crystal. They should be symmetrical to each other.
Notice any bubbles or scratches. These are indications that the crystal is fake.
Keep the crystal to the light. Notice any residue or melting. These are signs of a manufactured crystal.
Look for vertical lines. Real crystal will have vertical lines at almost any angle.
Lick the crystal. Real crystal should be cold even on a hot summer day, while fake crystal is not cold in the heat.
Look for any impurities on the crystal. Real crystal almost always has impurities.
Hold the crystal up the the sun or another bright light. Look for faint horizontal stripes or flowering spike-like formations, also called catkin. This is a sign of a real crystal.