Many blades are decorated with spiritual artifact(s). Most of them are organic origin (plant: fruit leaf, annimal: skin stag horn, claw, human: hair nail, cloth). There 's some "inorganic" spiritual artifact such as iron ore, pyrite, tin, copper. And most of them are "filled" in the hilt.
This embedded stag hilt 's an exceptional case.
As far as I know, gemstones are not considered very powerful. They were used as decorative and class representative materials (e.g. King 's sword 's highly decorated with gemstones).