Ya, I saw that after I posted. From the photo taken above above it looked like Zinc Sulfide powder or perhaps Aluminum oxide.
Safety glass breaks up in small pieces, so if someone falls into a sheet of large glass, it explodes into small chunks, and does not cut them in half. It has a sand appearance in the photographs, but it is small pieces of safety glass from the windows in the photograph. The windows are insulated, meaning there are two or three separate windows in each window opening. A vacuum or seal is between each window to make the window more resistant to letting in temperature changes. One window shows one pane of glass did not break, but the outer window did.
If safety glass is laminated, it will retain its position in the window frame, as in a windshield of a car. This type of safety glass is often not tempered, and is two close layers of glass with a sandwich of clear plastic between them, to give the windshield strength. Tempered glass is stronger than regular glass, but when it breaks, it shatters, almost with a boom, all letting go in a dramatic effect. Most side and back glass in cars is tempered safety glass. Most storefronts if they are safety glass, are tempered. Tempered glass is less expensive than laminated safety glass. Most building codes, require safety glass, if there is a chance a person could fall through the glass, as in low windows, or glass storefront doors.
