If you have setup Automated Ordering with us but not set up shipping locations when someone add diamonds or gemstones to their cart, they will not appear in the actual cart to checkout.
Please follow the below steps and this will work as expected:
Open your Nivoda Connect app within Shopify > Settings > Order & Fulfilment > Set up shipping rates
General shipping rates>
Scroll down to Nivoda Fulfilment > Add rates > Select the appropriate update based on your current setup within Shopify