"Hexagonal-rhombohedral. Crystals are very varied in habitat, often highly complex. Over 300 different…
"Hexagonal-rhombohedral. Crystals usually prismatic in habit or tapering hexagonal pyramids." —…
"Hexagonal-rhombohedral. Crystals usually prismatic in habit or tapering hexagonal pyramids." —…
"Hexagonal-rhombohedral. Crystals usually thick to thin tabular. Basal planes prominent, often showing…
"Hexagonal-rhombohedral. Crystals usually thick to thin tabular. Basal planes prominent, often showing…
"Hexagonal-rhombohedral. Crystals usually thick to thin tabular. Basal planes prominent, often showing…
"The vertical crystallographic axis is one of trigonal symmetry, and the three horizontal crystallographic…
"...in this figure the thicker lines are the projections of the three planes of symmetry, and on these…