Tavistockite is a rare mineral that belongs to the phyllosilicate group. It is named after its discovery locality, Tavistock, Devon, England. Tavistockite is characterized by its unique crystal structure and composition, making it quite distinctive and sought after among mineral collectors and geologists.
The mineral is typically found in granitic pegmatites, where it forms in association with other minerals such as albite, quartz, and tourmaline. It commonly occurs as platy or bladed crystals, often stacked together to form aggregates or rosette-like structures. Tavistockite can exhibit different colors, including shades of gray, brown, yellow, and green, depending on impurities present in its composition.
Chemically, tavistockite is a hydrated potassium sodium iron aluminum silicate. Its chemical formula is usually expressed as (K,Na) 2 (Fe2+,Fe3+, Al) 3 (Al, Si) 12 O 30 (OH) 10 ·14H 2 O. This composition indicates the presence of several essential elements, including iron, aluminum, potassium, and sodium, as well as numerous water molecules in its crystal structure.
In terms of its physical properties, tavistockite is relatively soft, scoring about 3.5-4 on the Mohs scale of mineral hardness. It also exhibits a pearly luster and has perfect cleavage along its crystallographic planes. Additionally, tavistockite has a specific gravity ranging between 2.81 to 2.88, which is relatively low compared to many other minerals.
Due to its scarcity and aesthetic appeal, tavistockite is primarily valued for its beauty and is highly sought after by mineral collectors and enthusiasts
