Aeschynite is found in rare earth rich granite pegmatites, a slow cooling igneous intrusive rock. Aeschynite is associated with minerals such as quartz , feldspars , zircon , columbite , xenotime , monazite , tantalite and other rare earth minerals. Aeschynite forms well shaped crystals at times, is associated with other rare minerals and can be an interesting specimen in someone's collection. Color is black to dark brown or yellowish brown in smaller crystals. Luster is vitreous to adamantine or pitchy when more massive.
Crystals are nearly opaque in massive forms and translucent in small crystals.
Crystal Habits include tabular to prismatic almost blocky crystals, some with well formed domal terminations. Cleavage is absent. Fracture is conchoidal. Streak is reddish brown or reddish yellow. Associated Minerals include quartz , feldspars , euxenite , fergusonite , monazite , columbite , tantalite , allanite , gadolinite , xenotime and zircon.