What is the difference between total quartz and respirable quartz as listed in the SDS?

Quartz is comprised of silicon and oxygen the second most abundant mineral found on earth.  The size of the quartz particle determines the inhalation hazard.  For example, quartz crystals that are larger than 10 microns pose little inhalation hazard.  In our case, this is described as “Total Quartz” within our SDS.  As OSHA points out, as well as the NIOSH and ACGIH, it is the respirable crystalline silica fraction that poses the true inhalation health hazard.  BARTON has confirmed that the respirable quartz fraction contained within our garnet abrasives is less than 0.1%.