Asbestos fibers become airborne quite easily but crystalline silica often found in solid form needs to be manipulated in order to be extracted as silica dust
Asbestos is dangerous enough to cause harm with minimal exposure but crystalline silica causes illness only after higher levels of exposure.
Though crystalline silica is hazardous and causes serious diseases, it can impact only certain people who have been working in specific jobs.
Asbestos is different because it can affect almost any person even though if he/she was not associated with the asbestos industry. This is because asbestos was ubiquitously used in the walls and pipes as insulation in most workplaces.
Asbestos material becomes instantaneously hazardous once it cracks and its fibers get released into the air but crystalline silica, though easily damaged, its dust causes harm only if inhaled in larger quantities.