Diamond doesn't melt, where did you read this? There are no diamond rivers on neptune, however it is believed to rain diamonds there. Go put a 3500c flame on a diamond, it would burn, not melt. Diamonds do NOT melt. If diamonds were meltable, people would have melted them to make flawless diamonds and regular diamonds would probably be cheaper. Just tell me, where did you learn this?
A bit of a necro, but in case someone says it's relevent, it's not, the question and the Neptune part has already been answered.
Diamond was not made to be diamond. It was made to be indestructable solid with a creative name.
agreed, molten diamond is one of the most STUPID ideas ive heard of in my TPT experience
they don't melt, but they do burn...