The Jennings River occurrence is located near Logjam Creek on the Nisutlin Plateau of northwestern British Columbia, about 127 kilometres northeast of the community of Atlin. Fluorite and beryl are accessory minerals in quartz veins in felsic dikes.

Fluorite occurs especially in the southwest part of a zone of sheeted dikes which is part of a felsic dike complex extending north of the Yukon-British Columbia border and which are related to monzonitic granite of the Early Cretaceous Logtung stock. Blue-green beryl occurs as slender prismatic crystals up to 3 centimetres long. The occurrence forms part of the Logtung tungsten molybdenum porphyry system (104O 016).