cervantite
Cervantite is a rare antimony oxide mineral with the chemical formula Sb3+Sb5+O4. It is a dimorph of bindheimite, meaning it has the same chemical composition but a different crystal structure. Cervantite typically forms in oxidized antimony deposits and is often associated with other antimony minerals like stibnite, senarmontite, and valentinite. It commonly occurs as fine-grained masses, crusts, or as distinct prismatic crystals. The color of cervantite ranges from pale yellow to brownish yellow, and it has a white streak. Its hardness on the Mohs scale is between 4 and 5, and it has a specific gravity of approximately 5.9. Cervantite is brittle and exhibits conchoidal to uneven fracture. It is found in various locations worldwide, including in China, Spain, and the United States. Due to its rarity, it is not of significant economic importance for antimony extraction, although it can be a minor source. Its identification in the field often requires microscopic examination or chemical analysis due to its resemblance to other antimony oxides.