Medium Rock Candy Lump Crystals (Sugar Rock Gems) The best sweetener for cocktails and hot drinks like coffee, and tea. Add a touch of flavor and sweetness to your morning drink. A delightful addition to any candy buffet or special occasion. perfect way to satisfy your sweet tooth. Rock candy crystal (rock sugar) is made by a crystallization process as diamond produces in nature, just with different ingredients. This process breaks apart sugar's molecular crystal lattice. After removing all impurities, in a high temperature and a specific time, the process allows producing larger and purer crystal of sugar that is known as classic rock candy crystals.