Crystallog. [f. L. beryllus, a. Gr. βήρυλλος beryl + -OID.] A geometrical solid consisting of two twelve-sided pyramids put base to base, as in the beryl.
1850. Dana, Min., 57. The form mPn completed is a double twelve-sided pyramid or berylloid.
Crystallog. [f. L. beryllus, a. Gr. βήρυλλος beryl + -OID.] A geometrical solid consisting of two twelve-sided pyramids put base to base, as in the beryl.
1850. Dana, Min., 57. The form mPn completed is a double twelve-sided pyramid or berylloid.
