Mum searched frantically, wanting diameter for pipe (10)

I believe the answer is:

meerschaum

I'm a little stuck... Click here to teach me more about this clue!

'for pipe' is the definition.
(type of tobacco pipe)

I can't explain the rest of the clue.

(Other definitions for meerschaum that I've seen before include "Clay tobacco pipe" , "It's smoked" , "I'm puffed!" , "Type of clay pipe" , "e.g. Tobacco pipe" .)

I've seen this clue in The Independent.

Want a hint initially instead of a full solution? Install my app