Tombarthite-(Y).Formula: Y 4 (Si,H 4 ) 4 O 12-x (OH) 4+2x (x ≤ 4) System: Monoclinic Colour: Brown- black Hardness: 5 - 6 Named after Thomas Fredrik Weiby Barth (1899-1971), professor of geology, Oslo University, Norway.Type Locality: Høgetveit (Høgtveit), Evje og Hornnes, Aust-Agder, Norway.
Calderite is a mineral in the garnet group with the chemical formula (Mn2+, Ca)3(Fe3+, Al)2(SiO4)3. It is dark reddish brown to dark yellowish in color and generally granular massive in form.Mohs scale hardness 6.5-7.5. It was named for geologist James Calder who worked on the geology of India.
Imilac, Atacama Desert, Atacama, Chile, Stony-Iron, This exquisite pallasite, with its beautiful large lime-green crystals, was found in 1822 in a valley southwest of Imilac, Chile. The olivine crystals are embedded in a nickel-iron matrix, which is believed to be formed during the formation of a planet.
Boulder Opal Specimen - Discovered in the southern-most opal mining region of Queensland known for the occurrence of precious opal in siliceous ironstone nodules—these are referred to in the mineral hobby as "nobbies". The ironstone matrix has been polished to reveal the brilliant play-of-color of the opal—the result of silica seeping into fissures—forming an intricate and very gemmy spiders web pattern throughout in electric purple, neon blue and green as well as tangerine orange colors.