Aventurine (blue)

Blue aventurine is a blue colour variety of aventurine, a natural quartzite or quartz rock whose platy inclusions can make it glitter (aventurescence); included dumortierite, a blue borosilicate mineral, produces the blue colour. Much blue material in the bead trade shows little sparkle: the Japanese retailer Pascle says its blue aventurine is for that reason also called blue quartzite. It overlaps with dumortierite quartz, and blue quartz-based beads may also be dyed.