Lorándite

![Crystal structure of lorandite. Violet atoms are arsenic, yellow are sulfur and brown are thallium.[7]](/uploads/202501/24/Loranditestructure4516.png)

Lorándite is a thallium arsenic sulfosalt with the chemical formula: TlAsS2. Though rare, it is the most common thallium-bearing mineral. Lorandite occurs in low-temperature hydrothermal associations and in gold and mercury ore deposits. Associated minerals include stibnite, realgar, orpiment, cinnabar, vrbaite, greigite, marcasite, pyrite, tetrahedrite, antimonian sphalerite, arsenic and barite.