Around a thousand scattered pearls glisten (7)
I believe the answer is:
sparkle
'glisten' is the definition.
('sparkle' can be a synonym of 'glisten')
'around a thousand scattered pearls' is the wordplay.
'around' is an insertion indicator.
'a thousand' becomes 'k' ('K' can be a synonym of 'thousand').
'scattered' is an anagram indicator.
'pearls' with letters rearranged gives 'sparle'.
'k' put into 'sparle' is 'SPARKLE'.
(Other definitions for sparkle that I've seen before include "Glitter, shine" , "Glitter, effervesce" , "Glisten" , "Shine brightly" , "Flashpoint" .)