and also lab-grown diamonds have a different reaction to light.
Natural diamonds typically emit blue fluorescence, while some lab-grown diamonds may show stronger, inconsistent, or different colors (e.g., orange, green, or yellow).
After turning off the UV light, observe if the diamond continues to glow (phosphorescence), natural diamonds don't.
Natural diamonds have variety as well. Just not the ones sold in jewelry stores, because they all generally come from the same DeBeers-owned mines. Diamonds are gemstones that can be found all over the world, with each location producing stones with their own unique properties.