Here are chia seeds (Salvia hispanica). Wikipedia says they are small flattened ovals, with average size 2.1 x 1.3 x 0.8 mm, and average weight of 1.3 mg. On the lower right is a 0.5 mm diameter pencil lead for scale. Chia seed is known as a nutritious food and is the namesake of the Chia Pet. In Aztec culture it was the third most important crop behind corn and beans, and ahead of amaranth.
Equipment used: Canon EOS Rebel T5i with 49 mm long extension tube.