09/09/2026
ROCKHOUND MINUTE: What makes agate banded? 🤔
Yesterday we showed off our agate wind chimes, and all those little slices had something in common. The gorgeous banding.
But what actually makes it?
Agate commonly forms when silica-rich water enters cavities within rock. Over time, silica is deposited along the walls of the cavity in extremely fine layers of chalcedony, a microcrystalline form of silica.
As the agate grows, changes in chemistry, impurities and growth conditions can cause one layer to look different from the next. Layer after layer builds inward, often following the shape of the cavity and creating the bands and patterns we recognize as agate.
Take a close look at this piece and you can actually follow those layers as they move inward. What you're seeing is a record of how the agate grew, one layer at a time. Slice agate thin enough and light can pass through it, really showcasing that banding. Just like we saw in yesterday's agate wind chimes. 💚
Every Stone Has a Story.