This Scottish carnelian crystal has the impression of  banding around the outer layer. Let me find my glasses...
I can see a light white band, followed by a yellow layer, with a slight red line through that outer layer. Inside the yellow is a nice layer of clear chalcedony leading into a central quartz pocket. It has a chalcedony skin in carnelian crystal colours.
This is an Ayrshire mineral specimen which is trying hard to be a real agate one day. There is something odd about the shape of the central quartz too. It almost looks like calcite except it is too hard and has the wrong luster. It may be a mineral I am unfamiliar with.
This has been in the rock tumbler through four cycles and soap.