James Lankton notes that glazed quartz (I don't think chalcedony) beads have been found at Nishapur in Northeastern Iran in sites that date from C10-12, along with jet, faience and glass. Peter Francis thought the roughly carved panel beads might be quite a bit earlier from Sasanian times when Nishapur first became a major cultural and trading centre.

The later period makes more sense to me, because I think this strange technique of glazing stone evokes the glazed blue and turquoise tiles and other ceramics (vases, dishes, jugs) that Nishapur became famous for in early Islamic times. Here, for instance, is a photo of the mausoleum of the great Persian poet Attar (the perfumer) that dates from C12 also.

Best,

Will