The Heather showing occurs at an elevation of 1974 metres on the north face of Middle Sister peak, one of three peaks forming the Three Sisters Peak. The peak areas of Three Sisters Peak are underlain by the Hadrynian Three Sisters Formation (Windermere Supergroup) which comprises quartzite, conglomerate and schist. Within a few hundred metres to the west is the north trending contact with the Lower Paleozoic Quartzite Range Formation composed chiefly of quartzite (correlative with rocks of the Hamill Group).

The showing is located within a shear zone that strikes 35 to 45 degrees and dips almost vertically. A composite felsic and lamprophyric dyke system, now highly sheared and shattered, in the order of 3.5 metres wide, has intruded the shear zone. Although the latest map of the area would indicate that the occurrence is located in rock of the Three Sisters Formation early documents report that the dykes are intruded into quartzite of the Quartzite Range Formation. The quartzites have a strike of about 045 degrees with a steep northwesterly dip.

Silicification and quartz veining within the shear zone is common. An adit has been driven as drift for over 50 metres on the zone. The old workings expose as much as a 1.2 metre width of quartz along the side of the dyke. Sulphide mineralization is sparse to non-existent but visible gold has been observed in the quartz. A sample taken across 20 to 25 centimetres of felsite dyke material assayed 2.06 grams per tonne gold and a trace of silver. A 4 centimetre wide quartz vein assayed 4.80 grams per tonne gold and a trace of silver (Maconachie, 1938).