The algae retardant roofing granules 1 wherein {TAIL ~ said microvoids} in said second or outer layer have an average thickness of from about 0.05 micron to {HEAD ~ about 0.5 micron} 
The algae retardant roofing granules 1 wherein { TAIL ~ said microvoids } in said second or outer layer have an average thickness of from about 0.05 micron to { HEAD ~ about 0.5 micron }
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD