The new mineral chorewiczite (IMA2025-066), Pb 2 Fe 3+ (Te 6+ O 6 )(HCO 3 ), is an oxidationzone mineral found on a dump of the Delamar mine, Delamar district, Lincoln County, Nevada, USA, as well as at four other localities.It occurs as thin hexagonal plates up to about 0.1 mm across.The colour is yellow, cream-coloured or silvery white and the streak is white.Crystals are transparent to translucent with subadamantine to dull lustre.The tenacity is brittle, the Mohs hardness is about 2 and the fracture is irregular.The calculated density is 6.177 gcm -3 .The mineral is optically uniaxial (-) and nonpleochroic.Electron microprobe analyses provided the formula Pb 1.96 Fe 3+ 1.05 (Te 6+ 0.99 O 6 )(H 0.98 CO 3 ).Chorewiczite is trigonal, P312, a = 5.199(4), c = 8.583(4) , V = 200.9(3) 3 and Z = 1.The crystal structure (R 1 = 0.0698 for 141 I > 2 I reflections) contains sheets of edge-sharing octahedra centred alternately by Te 6+ and Fe 3+ cations.The sheets are flanked by lone-pair stereoactive Pb 2+ cations above and below hexagonal cavities in the sheets.The structures of mllerite and
Kampf et al. (Fri,) studied this question.