Wow!!
I am so impressed with the quick work carried out by the people here, from buying the stone (great, great gesture) to finding out where the deed happened is an astounding bit of work so congratulations to all involved.
Makrolon is used in industry a lot for machine guarding and I believe for riot shields but I stand to be corrected on that one.
Have a look here;
http://www.makrolon.com/BMS/DB-RSC/MakrolonCMSR6.nsf/id/home_en