Because the lusters are so similar, it is hard to distinguish in the pics here where the galena ends and the sphalerite begins. But in general, the galena has formed between the sphalerite crystals with strange smooth, curved faces, and as you can see, the sphalerites have these intricately stepped/tiered faces, with a shiny black luster. There is very little matrix here - this is almost all intergrown galena and sphalerite.