Weep, having broken last glass (7)
I believe the answer is:
crystal
'glass' is the definition.
(crystal is a kind of glass)
'weep having broken last' is the wordplay.
'weep' becomes 'cry' ('cry' can be a synonym of 'weep').
'having' is a charade indicator (letters next to each other).
'broken' indicates an anagram.
'last' anagrammed gives 'stal'.
'cry'+'stal'='CRYSTAL'
(Other definitions for crystal that I've seen before include "brilliant stuff" , "Globe for the fortune-teller" , "Very clear glass" , "The fortune teller may use a . . . . . . . ball" , "Highly-transparent glass" .)