Stone is left in Bolivian city university -- large one (5,6)
I believe the answer is:
lapis lazuli
'stone' is the definition.
(I've seen this before)
'is left in bolivian city university large one' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' indicates putting letters inside.
'bolivian city' becomes 'La Paz' (capital of Bolivia).
'university large' becomes 'ul' (this could be a standard abbreviation of which I'm unaware).
'one' becomes 'I' (Roman numeral).
'is'+'l'='isl'
'isl' put inside 'lapaz' is 'lapislaz'.
'lapislaz'+'ul'+'i'='LAPIS-LAZULI'
Can you help me to learn more?
(Another definition for lapis lazuli that I've seen is " Bright blue stone".)