cinnabar

{{Infobox mineral | name = Cinnabar | category = Sulfide mineral | boxwidth = | boxbgcolor =#B0120C | boxtextcolor = #fff | image = Cinnabarit 01.jpg | imagesize = 260px | caption = Cinnabar, Staatliches Museum für Naturkunde Karlsruhe, Germany | formula = Mercury(II) sulfide, HgS | IMAsymbol = Cin | molweight = | strunz = 2.CD.15a | system = Trigonal | class = Trapezohedral (32) (same H–M symbol) | symmetry = P3121, P3221 | unit cell = a = 4.145(2) Å, c = 9.496(2) Å, Z = 3 | color = Cochineal-red, towards brownish red and lead-gray | habit = Rhombohedral to tabular; granular to massive and as incrustations | twinning = Simple contact twins, twin plane {0001} | cleavage = Prismatic {100}, perfect | fracture = Uneven to subconchoidal | tenacity = Slightly sectile | mohs = 2.0–2.5 | luster = Adamantine to dull | refractive = nω = 2.905 nε = 3.256 | opticalprop = Uniaxial (+); very high relief | birefringence = δ = 0.351 | pleochroism = | streak = Scarlet | gravity = 8.176 | density = | melt = | fusibility = | diagnostic = | solubility = water(Ksp at 25 °C = ) | diaphaneity = Transparent in thin pieces | other = | references = }}

Cinnabar (; ), also called cinnabarite () or mercurblende, is the bright scarlet to brick-red form of mercury(II) sulfide (HgS). It is the most common source ore for refining elemental mercury and is the historic source for the brilliant red or scarlet pigment termed vermilion and associated red mercury pigments.