The Agate Bluffs showing is situated on the northwest corner of Agate Mountain (Wilbert Hills), 10.5 kilometres southeast of Princeton.

Agate Mountain is comprised of a resistant capping of Eocene Princeton Group volcanics, resting on volcanics of the Upper Triassic Nicola Group and granodiorite of the Early Jurassic Bromley batholith. The Princeton Group rocks consist mostly of basalt and andesite with minor breccia and tuff.

Agate is found in pieces, several centimetres to 0.6 metre in diameter, scattered through talus just below the forestry look-out station, between elevations of 1040 and 1340 metres.

The agate is yellow to brown and green in colour, and translucent to opaque. Most of it is not well banded, but some of it resembles agatized wood. The stone is frequently badly fractured and thus not suitable for cutting and polishing, although some of the larger chunks would yield suitable lapidary material.