Black Agate Gemstone Bracelet Beautiful black agate gemstone beads, 3mm in size. Perfect for layering with other bracelets £9.00 Quantity: at £9.00 each Add To Basket 2 in stock. Black agate gemstones 3mm in size make this bracelet perfect for layer wearing with other bracelets. Black agate is a protective and grounding stone. Its calming and gives and inner strength to move on from stressful situations. Strung on jewellery elastic for an easy fit. *Please note I can not guarantee a gemstone properties, just that they are very beautiful.