Stone encountered in hasty scramble (8)
I believe the answer is:
amethyst
'stone' is the definition.
(I've seen this before)
'encountered in hasty scramble' is the wordplay.
'encountered' becomes 'met' ('meet' can be a synonym of 'encounter').
'in' is an insertion indicator.
'scramble' is an anagram indicator.
'hasty' with letters rearranged gives 'ahyst'.
'met' put within 'ahyst' is 'AMETHYST'.
(Other definitions for amethyst that I've seen before include "One showing sparkling facets" , "Something precious" , "what's in ring" , "Precious stone of purple quartz" , "Variety of quartz" .)