How to Make Artificial Diamonds

Beautiful diamonds can now be made quickly, but at high cost.

Creating synthetic diamonds was only a dream until 1953. Now using very specialized tools, beautiful diamonds can be created from humble graphite. Artificial diamonds are identical in all respects to mined diamonds, with the exception of being molded in a pressure vessel rather than in the earth. Natural diamonds are created as the intense weight of the earth and the heat underground press carbon into a very tightly compacted diamond over millions of years. The artificial process works in much the same way. Graphite is pressed in a specialized pressure vessel under great heat. This allows diamonds to be made in days rather than many millennia.

Things You'll Need

• Seed diamond (a small diamond)
• Diamond making pressure vessel (must be capable of generating 2700 degrees F and 58,000 atm of pressure)
• Diamond press plates (must be capable of withstanding the pressure and heat in the vessel)
• Ceramic reaction capsule
• Powdered graphite
• Hammer
• 30 ml of 1 molar hydrochloric acid
• 100 ml Erlenmeyer flask

Instructions

1. Put the seed diamond into the reaction capsule.

2. Layer graphite powder evenly around the seed diamond in the reaction capsule, filling to the top. The amount needed will vary depending on the size and shape of the ceramic capsule. Different model pressure vessels will use different sized ceramic capsules.

3. Press the bottom diamond press plates into place in the bottom of the vessel. They should form a solid half sphere with a raised platform in the center.

4. Put the ceramic capsule on top of the raised platform in the center of the press plates.

5. Arrange the top press plates to complete the solid sphere around the ceramic reaction capsule. Close the pressure vessel.

6. Set the pressure vessel to 2,700 degrees F and 58,000 atmospheres of pressure. Run for four days before turning off the pressure vessel.

7. Vent pressure and allow the vessel to cool. Different model vessels will have different controls to do this.

8. Remove the top half sphere of pressure plates. Then remove ceramic capsule.

9. Tap the ceramic vessel gently with a hammer to open the vessel. There should be a black lump in the center. This is the pressed graphite; the diamond is in the center.

10. Pour the hydrochloric acid into the Erlenmeyer flask. Dissolve the graphite lump in the acid, this should take 30 minutes to an hour.

11. Retrieve the diamond. It will not dissolve in the acid.

Tips & Warnings

• Take care when operating the pressure vessel. Pay attention to manufacturer's instructions. The pressures and heat involved may cause an explosion if improperly done. Use safety precautions when handling acid.

References

• American Museum of Natural History: Growing Diamonds
• YouTube: Science Channel: How do They Do That--Man Made Diamonds