delindeite

{{Infobox mineral | name = Delindeite | boxwidth = | boxbgcolor = #e7dada | image = Delindeite-741009.jpg | imagesize = | alt = | caption = Platy crystals of delindeite (red) on benitoite from California State Gem Mine, Santa Rita Peak, California | category = Sorosilicate minerals, seidozerite supergroup, lamprophyllite group | formula = | IMAsymbol = Dde | molweight = 902.60 g/mol | strunz = 9.BE.60 | dana = 56.2.6c.2 | system = Monoclinic | class = 2/m - Prismatic | symmetry = B2/m (no. 12) | unit cell = 1 | color = Light pinkish-grey to red | habit = Lath-shaped crystals or flakes, forming compact spherulitic aggregates, to 1 mm, some are fibrous | twinning = Submicroscopic on {100} | cleavage = Distinct/Good [001] Good | fracture = Irregular/Uneven | tenacity = Brittle | luster = Resinous, Pearly | streak = White | diaphaneity = Translucent | gravity = 3.3 | opticalprop = Biaxial (+) | refractive = nα = 1.79 nβ = 1.825 nγ = 1.982 | birefringence = δ = 0.192 | pleochroism = Non-pleochroic | 2V = Measured: 54°, Calculated: 54° | dispersion = single | fluorescence = | impurities = Mg | references = }}

Delindeite is a very rare titanium sorosilicate mineral in the lamprophyllite group and seidozerite supergroup. It was named in honor of Henry Samuel de Linde, an amateur mineralogist who was the former owner of the Diamond Jo quarry, Arkansas, where the mineral was first discovered in 1987. It is a secondary mineral formed under oxidizing conditions from a titanium-bearing nepheline and syenite.