Final answer:
Angular grains can indicate minimal sediment transport and are commonly found in conglomerates and biogenic sedimentary rocks. They are not typically microcrystalline.
Step-by-step explanation:
Angular grains can indicate minimal sediment transport. They are commonly found in conglomerates, which are sedimentary rocks composed of rounded fragments. While angular grains are not specific to any particular type of rock, they can occur in biogenic sedimentary rocks such as fossiliferous limestone. Angular grains are generally not microcrystalline, as they are larger in size compared to microcrystalline grains.