The gem dealer Color Line, at the southern end of the main street (on the left as you come from Ranohira), offers tours of the sapphire mines. Far from destroying the authenticity, it's fully part of it, taking you out to the rough-cut mines and explaining the whole process and intrigue. The guide, Mohammed, speaks French and a little English. Tours last 45 minutes to an hour.
Color Line also owns a gem showroom and workshop.