• Boulangerite is the mixed sulfide of lead and antimony (Pb5Sb4S11) which was discovered by Charles Louis Boulanger. The artistic picture shows the almost complete orthorhombic unit cell (tilted projection of the a-b plane) with lead sites being highlighted as polyhedrons. Antimony and sulfur are shown as brown and yellow spheres respectively. All three elements of the framework are present in at least two different coordination spheres. The symmetry along the c-axis translates into the one dimensional crystal habitus. The diameter of the individual boulangerite hairs of the photographed specimen is comparable to that of human hair (approx. 100 micrometer). The tuft is surrounded by galena (black mineral) and both minerals are supported by a rock that is essentially composed of siderite (yellow) and quartz (white). Galena (PbS) provides lead and sulfur as well as antimony which is known to occupy lead sites. The sample originates from Příbram (Czech Republic).
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