rock-candy
‘a hard confection that is made by cooling a concentrated sugar syrup into large, clear crystals around a piece of string or a stick’
Lexical development traced from the Tamil root:
E. rock-candy < rock + candy ‘crystallized sugar’ < O.F. çucre candi ‘sugar candy’ < Arab. qandi < Pers. qand ‘cane sugar’ < perhaps Dravidian (cf.: Tam. kantu ‘candy,’ kattu ‘to harden, condense’) < kand < Tamil kaṇṭu