rankinite

Rankinite is a rare mineral species that belongs to the zeolite group. It has the chemical formula Ca3Si3O10(OH)2 ∙ 6H2O and is typically found in hydrothermal veins and skarns, which are metamorphic rocks rich in calcium, iron, and magnesium. Its crystal structure consists of a framework of silicon and oxygen atoms, which is composed of three-membered silicate chains.

Rankinite was first discovered in 1970 at a skarn deposit in Yakutia, Russia. Since then, it has been reported from several other localities around the world, including the United States, Canada, and Brazil. The mineral is often associated with other zeolites, such as clinoptilolite and mordenite, and sometimes occurs in combination with other minerals like calcite, quartz, and pyrite.

Rankinite has a characteristic pinkish-red to reddish-brown color and a vitreous luster. It is relatively soft, with a Mohs hardness of around 4-5, and has a distinct cleavage. Synthetic rankinite has also been produced, and it has been studied for its potential use as a catalyst and adsorbent.

The mineral was named after A.V. Ramm, a Russian geologist, and the suffix "-ite," which is a common ending for mineral names. Rankinite is relatively rare, making up a small percentage of the zeolite group, and its finds are often significant geological discoveries that shed light on the formation processes of skarn deposits and hydrothermal vein systems.