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