The Rhyolite showing is located about 600 metres south of the Tis showing on the westerly slopes of Mount Brown, about 19 kilometres south of Stewart. The showing was first identified in 1990 and lies close to a glacial tongue about 2.3 kilometres west of the summit of Mount Brown.

The Rhyolite showing occurs in a 40 by 400 metre zone of silicified rhyodacite and consists of small pods, up to 20 centimetres by 2 metres, of massive pyrrhotite that is concentrated near the upper contact with argillite. Hostrocks are part of the Lower-Middle Jurassic Hazelton Group. The pods are parallel to bedding that is developed at a strike of 350 degrees with a steep easterly dip; in one pod 10 per cent sphalerite was observed. A rock sample (89953) analysed 6.42 per cent zinc and 109.4 grams per tonne silver (Assessment Report 20813).

In 1990, Tenajon Resources Corp. conducted geological mapping and rock sampling which resulted in the discovery of the Tis and Rhyolite showings. In 2006, an exploration program was conducted on the Praxis Project on behalf of Mineral Hill Industries Ltd. which covers this ground.

Granby Gold Inc. conducted geological mapping, airborne magnetometer and gamma ray spectrometry surveys (and geological interpretation of the same) over their East Georgie River project area, including the Rhyolite showing, from 2013 to 2020.