Jamesonite is a sulfosalt mineral with formula Pb4FeSb6S14.
An important occurrence of Jamesonite in Quartz is from Pitangui, Belo Horizonte, Minas Gerais, Brazil. It is found in the sames quartz crystals that produce Ankangite (Mannardite) and Celsian inclusions (see).
Some Jamesonite crystals appear to be partially or totally replaced by yet undetermined Sb white-yellow alteration minerals, that can be Valentinite or Cervantite. Associated with jamesonite have been found also small, clear, tabular crystals of Fluorapatite and the very rare mineral Cebaite (Ba3Ce2(CO3)5F2). This paragenesis is younger than ankangite-celsian because it grows in a higher portion of the quartz crystals.

Left: Quartz crystal with Jamesonite phantom and Ankangite crystals near the base. Center: Jamesonite. Right: Altered Jamesonite in possibly Valentinite or Cervantite.