Astrophyllite

From the Greek words meaning “star” and “leaf,”  Astrophyllite (as-TRO-fi-lite), contains big flattened crystals that color-shift from chocolate-brown to startling bronze as the stone is moved. The background is white feldspar. This material is nearly impossible to cut: The rough looks very pretty but spalls apart like a bar of soap when put to a saw. But apparently some people have a secret lapidary technique that not only works, but brings out the beauty of the glimmering bronze rutiles. This stone is not hard (similar to Azurite in hardness), so it is suggested that it not be used for belt-buckles or other high-wear jewelry.