the berk
know what you're holding
the agate guide
lake superior agate · by type
Born in lava about 1.1 billion years ago, tumbled by glaciers and surf ever since. One species of stone, many personalities — every single one a one-of-one.
fortification agate
the classic
Concentric bands following the stone's outline like fortress walls. The standard every other type riffs on.
eye agate
rare · the chase
Perfect circular "eyes" — banded hemispheres cut in cross-section. The more eyes, the bigger the find.
water-level agate
uncommon
Straight, flat parallel bands — silica settled by gravity like sediment in a jar. A built-in ancient level.
tube agate
uncommon
Round or oval "tubes" punched through the banding — mineral rods the agate grew around, seen end-on.
sagenite agate
rare
Needle-like mineral sprays fanning through the stone — frozen fireworks under the surface.
moss agate
rare here
Green-black mossy inclusions instead of bands. Common worldwide, a genuine prize on Superior shores.
shadow agate
rare
Tight translucent banding that throws a moving "shadow" when you tilt it in the light. Has to be seen.
paint agate
uncommon
Dense, opaque bands in saturated reds and oranges — looks hand-painted rather than glassy.
peeler
common find, great teacher
Outer husk "peeling" away to expose the banding beneath — nature's own cross-section, no saw needed.
how to spot one before you scoop
Look for a waxy, glassy luster where wet stones around it look flat · translucence at thin edges when held to the sun · a pitted, "orange-peel" husk · and any hint of banding on a worn face. When in doubt, wet it — agates light up.