Tazewell contains inclusions of schreibersite, haxonite, and troilite. Upon etching, it displays a Thomson (Widmanstätten) structure of finest texture due to its high Ni content of 17%. Tazewell was previously a member of the IIID iron group, but following a taxonomic revision by Wasson and Kallemeyn (2002), it is now included within the IAB iron-meteorite complex. On a NiAu diagram, Tazewell forms a low-Au, high-Ni subgroup (sLH) of the main group. To learn more about the relationships within the IAB complex, and among other iron chemical groups, click here.
The FeNi-chloride called Lawrencite was first identified in 1877 in a sample of Tazewell. This mineral absorbs moisture from the air and liquefies, a property known as deliquescence. The reaction with water and oxygen produces iron hydroxide and then hydrochloric acid, which may lead to the eventual disintegration of some meteorites. Tazewell is now the type locality for this mineral. The above specimen is a 2.9 g etched partial slice with a small remnant of fusion crust.