Value of 1.5 carat diamond

A diamond's value is a result of several factors, especially: carat weight, shape, color grade, cut quality, clarity, and which gemological laboratory did the certification.

Also, the "value" is different for a diamond dealer (who bases the value on the weekly Rapaport report), a diamond retailer (who adds in costs for the business's overhead), and someone interested in wearing or gifting the diamond (who needs to account for emotional value).

For an estimate of a diamond's retail value, plug its characteristics into a diamond search engine, which can show the retail prices at a dozen different retailers side-by-side.