Groutit iz Arizone, sa lokaliteta u severoistočnom delu okruga Apache, predstavlja retku i vizuelno upečatljivu kombinaciju crnih prizmatičnih kristala na jarko crvenoj podlozi. Ova kontrastna…
Opširnije GroutitTag: groutite
Groutite is a rare manganese oxide with the formula Mn3+O(OH). It forms dark, slender prismatic crystals, often in hydrothermal veins rich in manganese. Its hardness ranges from 3.5 to 4, and it crystallizes in the orthorhombic system. Groutite is often found alongside rhodochrosite, pyrolusite, and manganite. First described in 1945, it was named after American geologist Frank F. Grout. Though not widespread, groutite is highly valued by mineral collectors for its sharp crystal forms and metallic luster.