6.5" Apophyllite and Stilbite on Quartz Chalcedony Stalactites - India

This is a breathtaking, 6.5" wide by 5.6" tall mineral association containing lustrous, double-terminated apophyllite crystals, peach colored stilbite crystals and quartz/chalcedony. The quartz chalcedony formed as stalactites along the ceiling of a cavity, with apophyllite and stilbite crystals that formed over the quartz stalactite. This gorgeous specimen was collected from Maharashtra, India.

This specimen comes from the Deccan Traps (a large igneous province and one of the largest volcanic features on earth) in the Pune Province of India. In the course of quarrying for other materials or digging wells sometimes large pockets of zeolites and other minerals are unearthed in the volcanic rock.

Stilbite is probably the most common zeolite found in these 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. Apophyllite while not a zeolite itself is almost always found associated with zeolites in the same pockets. It has two crystal habits, a rectangular prism capped by a steep four sided pyramid or a pseudo-cubic structure. While not a well known mineral to the general public it is popular among mineral collectors due to it's pastel colors and beautiful crystal formations.

Silicon Dioxide, also known as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.

Chalcedony is any microcrystalline variety of silica composed of very fine intergrowths of quartz and moganite. Microcrystalline meaning the crystals are microscopic and cannot be observed by the naked eye. Both quartz and moganite have the same chemical formula SiO2 (silicon dioxide) but different crystal structures. When free from impurities, chalcedony is colorless and transparent. Dependent on impurities present during formation, chalcedony can form in a wide variety of colors including red, yellow, green, blue, purple, grey, white and numerous color hues in between. Chalcedony is quite hard, being a 7 on the Mohs Hardness Scale, which makes sense considering quartz is the benchmark mineral for a 7.
DETAILS
SPECIES
Apophyllite, Stilbite, Quartz & Quartz var. Chalcedony
LOCATION
Maharashtra, India
SIZE
6.5" wide, 5.6" tall
CATEGORY
ITEM
#176838