Chemical Formula: Na3Mg(CO3)2Cl
Locality: Searles Lake, San Bernardino Co., California.
Name Origin: Named after C. H. Northup (b.1861), grocer, of San Jose, California, who found the first specimen.
Northupite is an uncommon evaporite mineral, with the chemical formula Na3Mg(CO3)2Cl. It occurs as colourless to dark grey or brown octahedral crystals and as globular masses. In synthetic material it forms a series with tychite (Na6Mg2(CO3)4SO4).
It was discovered in 1895 at Searles Lake, San Bernardino County, California by C. H. Northup (born 1861) from San Jose, California, for whom Northupite is named.
It occurs associated with tychite, pirssonite at Searles Lake and with shortite, trona, pirssonite, gaylussite, labuntsovite, searlesite, norsethite, loughlinite, pyrite and quartz in the Green River Formation of Wyoming.
Discovery date : 1895
Town of Origin : SEARLES LAKE, BORAX LAKE, SAN BERNARDINO CO., CALIFORNIE
Country of Origin: USA
Optical and misc. Properties : Transparent
Refractive Inde : 1,51
Color: Brownish, Colorless, Gray, Gray brown, Yellow.
Diaphaneity: Transparent to translucent
Fracture: Brittle – Conchoidal – Very brittle fracture producing small, conchoidal fragments.
Hardness: 3.5-4 – Copper Penny-Fluorite
Luminescence: Fluorescent and Phosphorescent, Long UV=bright cream white.
Luster: Vitreous (Glassy)