Blue Dumotierite Quartz Necklace

This unique, Blue Dumortierite quartz necklace features a raw, fantasy cut stone set in a sterling silver (925), prong setting with a solid bail.  The small box chain is 18 inches.  The clasp is a sterling silver spring ring.   Approximate measurements of the stone:  20 mm long by 8 mm wide Dumortierite quartz is primarily composed of silicon dioxide (SiO2), which is the chemical composition of quartz, along with inclusions of dumortierite (Al₃(BO₃) (SiO₃) ₂), which is an aluminum borosilicate mineral.   It was discovered in 1881.  Color: Dumortierite quartz typically exhibits a blue to violet-blue color due to the presence of dumortierite inclusions, although it can also occur in other colors such as pink, brown, or gray. Luster: Vitreous to dull. Crystal System: Quartz: trigonal Hardness: 7 on the Mohs scale, the same as quartz.  Crystal Form: Typically occurs as prismatic hexagonal crystals, but often forms massive aggregates with fibrous texture due to the inclusion of dumortie