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