Sell Your Diamonds

Many clients visit Portland Gold Exchange to sell gold, silver, platinum, or palladium jewelry and are pleasantly surprised to learn that we also purchase natural diamonds and large precious gemstones.

While evaluating diamonds involves specialized grading parameters distinct from precious metal testing, our team guides you through every step of the process. Every evaluation is conducted 100% in plain view at your private testing station, providing full transparency and zero pressure to sell.

Rather than using flat bulk estimates, we evaluate natural diamonds according to established carat weight categories to ensure you receive maximum value:

• Smaller Diamonds (Under 0.15 Carats): Often referred to as accent stones or side stones, diamonds under 0.15 carats have their weight included with the gold or platinum mounting and are priced under our Premium Jewelry rate, adding extra value to your piece.
• Medium Diamonds (0.15 to 0.40 Carats): Diamonds in this size range receive an additional valuation bonus added directly to your jewelry payout quote.
• Larger Diamonds (0.40 Carats & Larger): Individual natural diamonds measuring 0.40 carats (approximately 5 mm) or larger are assessed using digital calipers, thermal conductivity diamond pens, and standard clarity/color parameters. This specialized review ensures your offer reflects the stone's specific physical characteristics and current market demand. (For diamonds 1.0 carat and larger, bringing official laboratory grading certificates, such as GIA, CGL, GRS, or SSEF, is highly recommended to secure maximum payout).

We purchase select large precious gemstones set within fine gold or platinum mountings under strict quality criteria:

• Accepted Gemstones: We purchase natural rubies (red), emeralds (green), and sapphires (blue or fancy colors) strictly if they are over 1.0 carat in size. These stones are evaluated on a case-by-case basis, and presenting recognized laboratory certification assists our team in confirming origin and quality.
• Explicit Gemstone Exclusions: We explicitly do not purchase pearls, amethyst, garnets, or tanzanite. For unpurchasable gemstones, our analysts estimate and deduct the physical stone weight from the total item weight to calculate the exact net precious metal value.