The word "teallite" is spelled with two L's despite it being pronounced as "teal-ite". This can be explained through the International Phonetic Alphabet (IPA) transcription of the word which is /ˈtiːəlaɪt/. The symbol for the "l" sound is "l", while "ll" represents a geminate or double "l" sound, which occurs when the "l" is prolonged or held longer than usual. Therefore, the double "l" in "teallite" indicates the need to hold the "l" sound longer when pronouncing the word.
Teallite is a rare sulfide mineral predominantly composed of lead and tin. It typically appears as small, metallic, opaque crystals, often black or gray in color. Its chemical formula is PbSnS2, reflecting its composition of lead (Pb), tin (Sn), and sulfur (S). Teallite belongs to the orthorhombic crystal system and has a hardness of 4.5 to 5 on the Mohs scale.
The mineral was named after its discoverer, Sir James Emerson Reynolds Teall, a British geologist and petrologist. It is often found in polymetallic hydrothermal deposits associated with other sulfide minerals such as chalcopyrite and galena. Teallite can be found in various regions worldwide, including Australia, Bolivia, China, Germany, and the United States.
Due to its high lead content, teallite has historically been of interest to miners and mineral collectors. It is sometimes used as a source of lead, tin, and sulfur extraction. However, its significance as an ore mineral is relatively low compared to other lead and tin sulfides.
In terms of its crystal structure and composition, teallite is closely related to other sulfide minerals, such as stannite (Cu2FeSnS4) and cylindrite (Pb3Sn4FeSb2S14). These minerals often form together or are found in association with each other in ore deposits.
The word "teallite" is derived from the name of a mineral named after Scottish geologist James Teall. James Teall (1848-1924) was a renowned British mineralogist and petrologist known for his contributions to the understanding of the geological history of Cornwall, England. In 1893, James Teall discovered a new mineral, which was subsequently named "teallite" in his honor. The term "teallite" was originally used specifically for a lead telluride mineral, but it is now also used as a general term to describe the mineral group that includes various lead telluride compounds.