The Diamond Lake pipe intruded a north-trending Proterozoic diabase dyke, surrounding Archean metasedimentary and overlying Paleozoic carbonate rocks approximately 153 Ma ago. The pipe consists of kimberlite breccia and a 2 m wide hypabyssal kimberlite dyke. The subcropping surface is approximately 250 m by 100 m. A second, smaller kimberlitic intrusion (possibly a dyke or small blow) subcrops 300 m south of the Diamond Lake pipe. The Diamond Lake pipe sits under the west flank of the north-trending Misema River Esker and is covered by 55 to 75 m of sand and gravel. The relative abundance of indicator minerals in the Diamond Lake kimberlite is: Mg-ilmenite > pyrope > Cr-diopside > chromite. Numerous kimberlite boulders have been transported by subglacial meltwater at least 2 km south from the pipe. Glacial dispersal from the Diamond Lake pipe is best defined by Mg-ilmenite, which can be traced at least 3 km southeast of the pipe in esker sediments.