There are at least two artists with this name:
1. Mother of Pearl are a London-baserd power trio led by vocalist Ali De Siati, with Marco Schnabl (guitar and programming), and Jonathan Neaves (drums). They released a self-titled EP in 2001, and the Volume EP in 2002.
2. Mother of Pearl are "Vancouver's all female jazz and blues quartet." They released Shebop! (A Century of Jazz Compositions by Canadian Women) in 2006.

Read more about Mother Of Pearl on Last.fm.