Here is buckwheat (Fagopyrum esculentum) grain. The grain is gluten free and is consumed by humans as porridge, in pancakes, noodles, and in beer making as an alternative to barley. The plant is native to southwestern China, and was first cultivated about 8000 years ago. These grains measure about 3.3 by 4.0 mm.
Equipment used: Canon EOS Rebel T5i with a standard zoom lens (EF-S 18-55 mm) on a 49 mm long extension tube.