heliotrope mineral, bloodstone, a cryptocrystalline mixture of quartz occurs mostly as jasper (opaque) or chalcedony

bead blood bloodstone blue cabochon chalcedony collection cryptocrystalline crystal cut cutout decorative gem gemmology gemological gemology gemstone geological geology green heliotrope hematite inclusions jasper jewelry mineral mineralogical mineralogy mixture natural nature object occurs opaque ornamental pebble piece polished quartz red resembles rock rolled sample semiprecious serpentine shining small spar specimen spot spots stain stone structure style surface texture translucent tumbled