Answer:

collet

AnswerCrossword Clue
COLLETGem-setting flange
COLLETSetting for a diamond.
COLLETMetal band or ring.
COLLETMetal band.
COLLETEnclosing rim for a jewel
COLLETEnclosing rim in which a jewel is set
COLLETRim in which a gem is set
COLLETJewelry setting
COLLETSocket for setting a gem