The two minerals have the same crystal shapes, symmetry and cleavage. The large volume of Galena that is processed for lead produces enough Silver as a by product to make Galena the leading ore of Silver. Color is lead to silver gray sometimes with a bluish tint. Luster is metallic to dull in weathered faces. Transparency crystals are opaque.
Spinel twinning is possible forming flattened crystals.
Also massive and granular. Cleavage is perfect in four direction forming cubes. Fracture is uneven and rarely seen because of the perfect cleavage. Streak is lead gray Associated Minerals are calcite , dolomite , sphalerite , pyrite and other sulfide minerals, also lead oxidation minerals such as cerussite and anglesite . Best Field Indicators are crystal habit, cleavage and, perhaps most importantly, density.