How much can you sell 1 diamond for?

Excuse me, could you please clarify for me the potential value of a single diamond when it comes to selling it? I understand that diamonds vary greatly in terms of quality, size, and rarity, but I'm curious about a general range or an average figure that one might expect to receive in exchange for a diamond of a certain standard. Could you provide some insight into how much a diamond of average quality and size might fetch on the market? Thank you for your time and expertise.