Soutulaite

Soutulaite is a rare and distinctive mineral that belongs to the sulfate class of minerals. It was first identified in 1972 at the type locality of the Poudrette quarry in Quebec, Canada, where it was discovered in association with other secondary minerals in a pegmatite. The mineral was named after the village of Saint-Sulpice, Quebec, where the quarry is located, with the suffix "-ite" indicating its mineralogical classification.

Soutulaite has a chemical composition of PbAl₃(SO₄)(OH)₆, meaning it consists of lead (Pb), aluminum (Al), sulfur (S), oxygen (O), and hydrogen (H). Its crystal system is hexagonal, and it typically forms as small, tabular crystals or crusts. The mineral is usually colorless to white, though it may appear pale yellow or grayish due to impurities. Soutulaite has a vitreous to pearly luster and is relatively soft, with a Mohs hardness of about 3 to 3.5.

The mineral is found in low-temperature hydrothermal environments, often associated with other secondary minerals such as barite, gypsum, and various aluminum sulfates. Due to its rarity, soutulaite is not commonly encountered in collections, and specimens are highly sought after by mineralogists and collectors. It is primarily known from its type locality in Quebec, though it has also been reported in other locations, including the United States and Russia.

Soutulaite is of interest to researchers studying secondary mineralization in pegmatites and other geological settings. Its unique composition and occurrence provide insights into the processes of mineral formation under specific conditions. While not economically significant, its rarity and aesthetic qualities make it a notable specimen for educational and display purposes.