jewellery = rings, bracelets, necklaces, watches, precious stones, ornament sets with jewels.

• The stolen jewellery has been recovered by the police.
• The thieves took nothing but cash and jewellery.
• You should keep expensive jewellery(NOT jewelleries) in a bank or safe.

jeweller’s = a shop which sells and repairs jewellery

• Scariachan bought the gold ornaments for his daughter’s wedding at a jeweller’s in Mumbai.
• I saw the same watch in a jeweller’s(NOT jewellery) at Calicut.