From Crystal Personalities by Patricia Troyer:
Clusters symbolize cooperation and harmony between dissimilar individuals
Represent individuals grouped together for maximum results
Actively and dramatically stimulate and boost creativity
Generate the desire to cooperate and harmonize with others
Boost and enhance psychic energy
Outstanding energy shield
Cleanses and energizes other stones, rooms, people, and all living things
Balances male and female energies
Choose a size range:
small 1" - 3"
medium 3" - 6"
large 6" - 9"
x-large 9" and greater