Knowra Crocoite Crocoite Crocoite is a bright orange-red lead chromate mineral, PbCrO₄, found chiefly in oxidized lead deposits. Its vivid color and slender crystals make it a distinctive mineral specimen.
Lead chromate : Lead chromate is an inorganic compound with the formula PbCrO₄, occurring naturally as crocoite and also made synthetically. Crocoite is the natural mineral form of this compound.
Crystal field theory : Crystal field theory describes how surrounding ions affect the energy levels of transition-metal d orbitals. It helps explain chromium-related optical behavior in minerals.
Dundas, Tasmania : Dundas is a historic mining district in western Tasmania, Australia, known for exceptionally fine crocoite specimens. Its mines produced many of the mineral’s most celebrated crystals.
Chrome yellow : Chrome yellow is a family of yellow pigments based on lead chromate and related compounds. Crocoite has the same basic compound as lead-chromate pigments, though it is a mineral specimen.
Monoclinic crystal system : The monoclinic crystal system has three unequal axes, with two intersecting at oblique angles and one perpendicular to their plane. Crocoite crystals belong to this system, shaping their elongated forms.
Charge-transfer transition : A charge-transfer transition moves an electron between different atoms or ions within a molecule or solid. Electronic transitions involving chromate account for crocoite’s strong visible color.
Adelaide Mine : The Adelaide Mine is a former lead mine near Dundas, Tasmania, renowned for crocoite specimens. It is one of the principal sources of fine Tasmanian crocoite.
Lead poisoning : Lead poisoning is illness caused by exposure to lead, which can damage the nervous system and other organs. Handling or ingesting crocoite dust can expose people to toxic lead.
Chromate : Chromate is the oxyanion CrO₄²⁻, in which chromium is in the +6 oxidation state. The chromate group is the anionic component in crocoite’s chemical formula.
Oxidation zone : An oxidation zone is the near-surface part of an ore deposit altered by oxygen-rich water and weathering. Crocoite forms where lead-bearing deposits undergo oxidation.
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