HOMOLOVI III XRD OF PREHISTORIC 'ADOBE' BRICK about 3"x 4"x 8" mid-dark terracotta color
		It appears to be basically a mix-perhaps a gathering from a nearby  alluvial deposit (seasonal maybe), but some of the clays may have been added to 'help hold it together' and for workability.  The constituents are mainly feldspars and quartz(sand)---the needle-like feldspar crystals probably interlock and give the brick strength---the more weight on top of each brick, the stronger the brick below.  Local material deposits could be easily compared.
				A ZOOMABLE PATTERN SOON!