All real diamonds have a resale value, whether naturally sourced or lab-created. Lab-grown diamonds are real diamonds and do command a resale value, depending on the retailer you have purchased from.
In reality, it is practically impossible to get fair value for your diamond jewellery, if you try to sell it to anybody other than the jewellery you bought it from. Even with mined diamods, you fetch the best resale value when you do a buyback with the brand you bought it from. It is the same with created diamonds. The retailer you have purchased your lab-grown diamond jewellery from, usually has their own policies regarding resale (buyback) and exchange.
It is important to note, that while this is a relatively new category, a lot of brands like DIVAA by ORRA are offering the same exchange and buyback policies to their customers, as mined diamond jewellery.
With the growing demand for lab-grown diamonds in India today, the prices of these diamonds are steadily increasing and if the retailer offers the same buyback / exchange policy as mined, you can probably get more value for your diamond jewellery.
Finally what matters is the reason or occasion why you want to buy diamond jewellery and as long as the retailer’s policies are transparent, you need to be aware of how you are spending your money.