Two Paths to Real Diamonds
Lab grown diamonds are produced using two main methods: CVD (Chemical Vapor Deposition) and HPHT (High Pressure High Temperature). Both produce real, gem-quality diamonds, but they differ in process, typical quality characteristics, and cost. Understanding these differences helps wholesalers make informed inventory decisions.
CVD: The Layer-by-Layer Method
CVD grows diamonds by depositing carbon atoms onto a diamond seed in a vacuum chamber. The process takes 2-8 weeks depending on size. CVD diamonds typically have: excellent clarity (fewer inclusions), natural colorless to near-colorless (D-H range), and may have subtle growth patterns visible under magnification. CVD is the most common method for gem-quality lab diamonds and is preferred for larger stones (1ct+).
HPHT: The Pressure Method
HPHT mimics natural diamond formation by subjecting carbon to extreme pressure and temperature. The process takes days to weeks. HPHT diamonds typically have: good clarity (may have metallic inclusions from the catalyst), colorless to fancy colors (HPHT excels at colored diamonds), and no growth patterns. HPHT is also used to treat/improve the color of existing diamonds (both lab and mined).
Quality Comparison
Clarity: CVD generally produces higher clarity (VVS-VS) more consistently. HPHT may have metallic flux inclusions (visible as tiny metallic specks).
Color: Both produce colorless (D-F) diamonds. HPHT is better for fancy colors (yellow, blue, pink). CVD may have slight brown/grey undertones in lower grades.
Cut: Both methods produce rough that can be cut to excellent grades. Cut quality depends on the cutter, not the growth method.
Identification: Both can be identified as lab-grown by specialized labs (IGI, GIA) using spectroscopy and fluorescence testing.
Price Differences
CVD and HPHT diamonds of the same quality grade are priced similarly — the growth method doesn't significantly affect retail price. However, HPHT may be slightly more affordable for certain sizes/colors due to production efficiency. The primary price factors remain the 4Cs (cut, color, clarity, carat), not the growth method.
Which Should You Stock?
For colorless engagement ring stones (D-F, VVS-VS): CVD is the standard and most widely available. For fancy colored diamonds: HPHT is preferred. For smaller accent stones (pavé, side stones): either works — HPHT may offer better pricing. Most retailers don't need to specify the growth method to customers — what matters is the certified 4Cs grade. Holycome sources both CVD and HPHT diamonds based on quality and availability.
Certification Matters
Regardless of method, always source certified lab diamonds. IGI and GIA certificates identify the growth method (CVD or HPHT) and provide full 4Cs grading. Certification assures customers of quality and authenticity. Avoid uncertified lab diamonds — they may have undisclosed treatments or quality issues.
Customer Education
Most customers don't know the difference between CVD and HPHT — and they don't need to. What matters is: "It's a real diamond, grown in a lab, with this certification and these grades." If asked, explain that both methods produce real diamonds, and the method doesn't affect beauty or durability. Focus on the 4Cs and certification, not the growth process.
Holycome's Lab Diamond Sourcing
Holycome sources both CVD and HPHT lab diamonds based on quality, size availability, and pricing. We prioritize D-F color, VVS-VS clarity, and excellent cut for all our lab diamond jewelry. Every stone comes with IGI or GIA certification. We select the best stone for each design — whether CVD or HPHT — ensuring consistent quality across our collection.
Explore certified lab grown diamonds — CVD and HPHT, factory direct.