As with many of the vague terms used to describe the various microcrystalline quartz forms, the exact definition of “agate” has never been officially determined. However, most agates include more than one color and the various sub-variety names often describe what the resulting color patterns most closely resemble (e.g. fortification agate, lace agate, tube agate, dendritic agate, banded agate, etc.).

While much of the above could also be equally applicable to jaspers, it is the stone’s translucency, or a lack thereof, that differentiates these two chalcedony groups, with most varieties of agate possessing some degree of translucency. This distinction can be most clearly seen when comparing the visual appearances of translucent moss agate and the similarly-named, opaque moss jasper.

The distinctive wavy parallel banding seen within banded agate make it perhaps the best-known sub-variety, with thin slices of the material being a staple of many gift shops.