Arvoiden

Arvoiden is a rare mineral described from hydrothermal veins in the Arvoid Basin. It is characterized by blue-green to olive-colored prismatic crystals that occur in fibrous and tabular aggregates. The mineral forms in low-temperature, oxidizing environments and is commonly associated with copper- and zinc-bearing sulfides as well as calcite. Chemically, arvoiden belongs to a hydrated silicate family with a variable composition, with aluminum and silicon as major constituents and calcium and trace metals such as copper.

It displays a Mohs hardness of about 5.5 to 6, a vitreous to pearly luster, and a color range from pale blue-green to olive. Crystals are translucent to transparent in well-formed specimens, with a white streak. Cleavage is imperfect in two directions; habit ranges from tabular to acicular.

Occurrence and formation: The type locality is the Arvoid Basin, in the Verdan Province. Arvoiden forms during late-stage hydrothermal alteration of ultramafic and metavolcanic rocks, in veins enriched by copper and zinc, under temperatures roughly 150–300°C.

Discovery and naming: Arvoiden was first described in a 2012 field report by researchers led by Dr. Lian Kestrel; the name honors the Arvoid region where it was first found, with the -en suffix indicating a mineral species in the naming convention used by the team. The International Mineralogical Association accepted the name in 2014.

Uses and significance: Arvoiden is primarily of interest to mineral collectors and researchers studying hydrothermal systems. It has limited industrial use but is sought as a specimen for its color and form, and is used as an indicator mineral for ore exploration.