rough edges; abrasiveness; harshness
Used for a person's character, words, or attitude that is sharp, unpolished, or lacking smoothness. Often appears in negative expressions like 圭角がない (lacking rough edges, mild-mannered).
edges of a gem
Original literal meaning referring to the cut edges or facets of a gemstone. Rarely used in modern Japanese outside of literary or technical contexts.
He had rough edges when he was young, but he has mellowed now.
His way of speaking has no sharpness, so he gets along well with everyone.
This gem has sharp edges and reflects light beautifully.