This bolete produces fruit bodies that are dark purple to chocolate brown in color with a smooth cap, a finely scaly stipe, and a reddish-brown spore print.

Originally described in 1874 as a species of Boletus, the fungus has also been classified in the genus Leccinum because of the scabers on the stipe, or in Tylopilus because of the color of the spore print.

The species was originally described as Boletus robustus by American mycologist Charles Christopher Frost in 1874, from specimens collected in Vermont.

[4] William Alphonso Murrill transferred the species to Ceriomyces in 1909,[5] but this genus is no longer recognized, having largely been subsumed into Boletus.

[13] In 2012, Halling and colleagues published molecular evidence indicating that the species did not belong in either Tylopilus or Leccinum as it does not share a recent common ancestor with either of those genera.

[14] Although Frost's reason for using this name is not known with certainty, Peter Roberts and Shelley Evans speculate "Perhaps it was the violet-brown colors, which are quite attractive in a formal, nineteenth-century manner.

[19] T. violatinctus, found in eastern North America, has whitish pores, a smooth stipe, and a somewhat paler cap than S. eximius.

A mycorrhizal species, the bolete has been recorded growing in association with plants from various genera, including Dicymbe, Dipterocarpus, Fagus, Hopea, Quercus, Shorea, and Tsuga.

[1] Although S. eximius has been reported from Thailand,[21] molecular analysis of Thai collections suggests that they represent a distinct, as-yet unnamed species.

[1] Sutorius eximius is typically considered an edible mushroom, and listed as so in several North American field guides.

[16] Charles McIlvaine and Louis Krieger both wrote favorably of the bolete's esculent properties, but a series of poisonings reported from the New England region and eastern Canada have cast doubt on its edibility.

According to Greg Marley, author Roger Phillips was the first to include a toxicity warning in his 1991 book Mushrooms of North America.

[22] Despite its revised status in North America, the lilac-brown bolete remains one of the most common fungi used as food by locals in the Hengduan Mountains region of southwestern China.