2.5" Red-Orange Stilbite Crystal on Chalcedony - India

Stilbite is a tectosilicate mineral of the zeolite group that is commonly found in zeolite deposits. Crystals often form flowery bowtie or hourglass-shaped structures and come in a variety of colors. Some of the most beautiful colorations are the pink or peach tints.

Chalcedony is any microcrystalline variety of silica composed of very fine intergrowths of quartz and mogánite: microcrystalline minerals have microscopic crystals that cannot be observed by the naked eye. Both quartz and mogánite have the same chemical formula SiO2 (silicon dioxide), but different crystal structures. When free from impurities, chalcedony is colorless and transparent. Depending on impurities present during formation, chalcedony can form in a wide variety of colors including red, yellow, green, blue, purple, grey, white, and numerous hues in between. Chalcedony is quite hard at 7 on the Mohs Hardness Scale: this matches its main component quartz, which is the benchmark mineral for the scale at 7.