1. Rock crystal is quartz in its purest form, composed of silicon and oxygen.

2. 27 A pair of rock crystal goblets engraved with the cipher of Peter the Great.

3. Designed as the traditional Aretinian so called “Fede Chianina” with collet set garnet and rock crystal table cut

4. Trying to be cool, I play a practical joke, slipping the leftovers from a salt rock crystal experiment into four milks at lunch

5. It has not been neutralized by an acid to make cocaine hydrochloride, the pure form of the chemical. Crack comes in a rock crystal form that can be heated and inhaled or smoked

6. Crystals of various sizes are found in nature—from the very large Crystals of quartz (rock crystal), fluorite, and feldspar, weighing up to several hundred kilograms, to the small Crystals of diamonds and other minerals

7. Crack cocaine is a highly potent and addictive stimulant processed from powdered cocaine and made to look like a rock crystal. Crack produces effects similar to that of powdered cocaine but comes with a higher number of health risks including lung trauma and bleeding.