Rhyolite, 2021, fiber - quilt, 34 x 48 in. / 86.36 x 121.92 cm.

Rhyolite, Anne Garretson, 2021, fiber - quilt, 34 x 48 in. / 86.36 x 121.92 cm.

The volcano that formed the Yellowstone caldera left a rock known as rhyolite, found in shades of grey, tan and pink.