Silestone 25 Year Warranty Silestone as a brand offers 25 years certified warranty, in writing. Only a global leader, one which is the largest producer of quartz surfaces, could once again draw ahead of the pack and offer a genuine 25-year warranty for Silestone. Requisites for fulfilment of the Silestone warranty: To activate your warranty, the user must provide a proof of purchase. Warranty is valid aftere online registration within 60 days of purchase. Activate warranty Any product that it was unregistered in the website during the 60 days after the purchase, will keep a warranty of 2 years if you have the invoice.