[2] In 2022 the species was transferred from Cortinarius and reclassified as Thaxterogaster argyrionus based on genomic data.

Initially bluish gray, the cap colour matures to pale grayish brown.

They start out greyish blue before changing to brownish violet when the spores mature.

[2] The specific epithet boreicyanites refers to its close relationship to Cortinarius cyanites, and its boreal distribution.

[2] Found in the boreal mixed forests of Europe (Sweden, Finland and Scotland).