US guides
Some US buyers want a natural diamond because that is what they were shown growing up. That is a real preference. It does not make the stone an investment account.
Lab-grown diamonds can also be worn for decades. Their resale in the US is weaker. If the heirloom goal is “she can sell it later for what we paid,” neither origin does that job.
Decide what the report should say — natural or laboratory-grown — and then buy the best cut you can see.
Use the two catalogs honestly. Do not let heirloom language skip the 360° view. Carat Mate ships the certified loose diamond and its lab report to United States addresses. Prices on the site are in USD. Wrong-item returns may be considered within 3 days of delivery, subject to review.