Of the estimated 100 European lunula known in Western Europe, some 80 originate in Ireland. The equivalent for the girl was the "lunula", a crescent moon amulet. The material removal rate is computed by area of lunula and the feed rate. Lunula black with a black mark above it. If one damages the lunula, the nail will be permanently deformed. Further analysis may indicate whether the lunula had been made of Irish or Scottish gold. The epithet "lunulata" 'crescent-shaped' is derived from Latin "lunula" for 'little moon'. The lunula is most noticeable on the thumb; however, not everyone's lunulae are visible. Lunula yellow with a black mark above it. The lunula is the visible part of the root of the nail. In Wilson's disease the blue color involves the lunula (most intense pigmentation) and fades proximally. In some cases, the eponychium may partially or completely cover the lunula. "Chaetodon lunula" is a nocturnal species that usually lives in small groups. Outlining the nail matrix, the lunula is a very delicate part of the nail structure.