Glendonite
Glendonite is really a variety of Calcite pseudomorphs after Ikaite. A pseudomorph is a mineral with the external kind that is a crystal of mineral, therefore, the internal chemistry of another. Ikaite is the version that is hydrated of, or Calcite could be the dehydrated variation of Ikaite. The chemical formula for Ikaite is CaCO3·6H2O. The chemical formula for Calcite is CaCO3, the same as for Ikaite but without the H2O. Ikaite readily dehydrates to Calcite in conditions above 8°C and it is typically found in near-freezing water in deep ocean locations or locations of cold seeps. A seep that is cool sometimes called a cold vent, occurs over cracks and fissures within the sea flooring caused by tectonic activity. These seeps allow hydrogen sulfide, methane and other liquids which can be hydrocarbon-rich “seep” from the planet. Ikaite is formed from the calcium mixture that is carbonate-rich the seeps.
When Ikaite is removed from its natural water that is cool, it rapidly disintegrates into anhydrous calcium carbonate and water, earning it the nickname “the melting mineral”. The pseudomorph that is resulting of after Ikaite is called “Glendonite” after the location where it was initially reported in 1905, Glendon, New South Wales, Australia. Ikaite is termed for the type locality at the Ikka Fjord (formerly spelt Ika), Greenland.
Glendonite’s most well know form is an arrangement that is radial of, reddish-brown or cinnamon-brown crystals. It has also been called the “rose stone” referring to the radial arrangement associated with the crystals offering it an appearance that is flower-like. Some have actually stated the “spikey” practice of the crystals looks more like a pine cone. Calcite pseudomorphs after Ikaite are known by several other names as well. These names are often after specific locations such as Jarrowite named after Jarrow, Northumberland, UK, and Fundy-lite named for the Bay of Fundy, Nova Scotia, Canada. Other names are regionally derived referring to the crystal’s uncommon shapes such as for instance Gersternkorner which will be German for barleycorn and Gennoishi which is hammerstones in Japanese and Molekryds meaning mole cross in Danish. There are also the names White Sea Hornets through the White Sea and the Kola Peninsula, Russia and Thinolite through the Greek term thinos, meaning shore, from associated with the occurrence in the tufa of Mono Lake, California, United States Of America.
Glendonite circulation: besides the “type locality” at Glendon, New South Wales (NSW), Australia, Glendonite is also found at these locations in Australia: Hunter Valley, Durham County, NSW; Wallaby Gully, Quarrobolong, Northumberland County, NSW and Yerila Creek, North Flinders Ranges, South Australia. In Canada at Eureka, Ellesmere Island, Nunavut Territory. In Japan at Koudo, Ueda City, Nagano Prefecture, Chubu region, Honshu Island. In Russia at the Olenitsa River, White Sea Coast, Kola Peninsula, Murmanskaja Oblast’, Northern Area. In the USA at Mono Lake, Mono County, California; as well as in Washington at Altoona, Wahkiakum County, and Five Mile Quarry, Porter, Grays Harbor County.
| Chemical Formula: | CaCO3 |
| Calcium Carbonate | |
| Crystal system: | Monoclinic |
| Crystal habit: | Nearly square prism; pyramidal; sigmoidal: square prism capped with oppositely canted pyramids; massive, tubular (tinolite VR.) |
| Hardness: | 3 |
| Luster: | Dull |
| Specific gravity: | 1.83 |
| Refractive index: | nα = 1.455 nβ = 1.538 nγ = 1.545 |
| Optical properties: | Biaxial (-) |
| Birefringence: | d = 0.090 |
