The silica content varies significantly based on the stone being cut. Engineered stone is apparently like 90%+ silica, with the rest being binders. Granite is apparently ~10-45% silica, while marble has a negligible amount.
The pamphlet said that in one study, a marble shop performing dry grinding (no wetting, nor other engineering controls) had airborne silica levels of 39-45 ug/m3, while a granite shop which also did not use engineering controls say 89-460ug/m3.
There's a OSHA/NIOSH pamphlet linked through the original article (https://www.osha.gov/sites/default/files/publications/OSHA37...) with table and additional details.
The pamphlet said that in one study, a marble shop performing dry grinding (no wetting, nor other engineering controls) had airborne silica levels of 39-45 ug/m3, while a granite shop which also did not use engineering controls say 89-460ug/m3.