It usually forms in rounded nodules or knobs which must be sliced open to bring out the internal pattern hidden in the stone. Literally hundreds of Agate types were coined with special variety names. Most of these are hardly known, and new ones are made up every year. Most of these names have no scientific support, and it is not in the scope of this guide to list all variety names. The list below cites only the well-known and commonly used variety names.
Some varieties have two names which are equally used.
Don't be surprised when you see the same definition for two different variety names. This is NOT a mistake. Blue Lace Agate - Agate with light blue bands in a lacy or wavy pattern. Botswana Agate - Agate from Botswana banded with fine, parallel lines, often with a preponderance of pink blending into white. Brecciated Agate - Agate with broken fragments naturally cemented together.