Orange brown crystals of the very rare Sb mineral monimoite from a locality in Sweden and only one of the very few known localities worldwide: Harstigen Mine, Pajsberg, Persberg, Filipstad, Värmland County. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Monimolite
A lead antimonate mineral — an ochre-yellow secondary mineral of oxidized lead-antimony deposits.
Intro adapted from Wikipedia (CC BY-SA).
Monimolite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Pb₂Sb⁵⁺₂O₇.
It is a member of the Pyrochlore structural group.
Key properties: Mohs hardness 4.5–6; specific gravity 5.94–7.29; Straw-yellow to cinnamon-brown streak; Greasy to adamantine luster.
IMA symbol Mml, IMA status: questionable, named in 1866.
Found in calcite veins in an iron and manganese deposit.
It is found associated with Tephroite, calcite.
Its name comes from the Greek for stable, as it is decomposed chemically only with great difficulty.