The thieves struck at the Leeds Road premises about 8pm on Thursday, November 14, and items taken include Tiffany bracelets, diamond, cameo and turquoise brooches, emerald and diamond, sapphire and solitaire rings.
Also stolen were Tiffany and pearl necklaces, bloodstone and diamond heart pendants, and pearl and clip-on earrings, and Omega, Mudu and Longines wristwatches.
Anyone with information should contact Harrogate police on 101, select option 2 and ask for David Mackay. Alternatively, information can be emailed to firstname.lastname@example.org. Or call Crimestoppers anonymously on 0800 555111, quoting reference number 12130198121.