Technology & Quality (HPHT vs CVD)

HPHT growth creates a crystal structure identical to top-tier Type IIa natural diamonds, naturally yielding D-E colors without post-growth treatment. CVD often requires masking (HPHT treatment) to remove brown tints to achieve high colors.

Our premium production line filters for 'No Blue Nuance'. While boron can cause blue tints in standard HPHT, we use advanced catalysis control to ensure our D-E stones are purely colorless, specific for high-end jewelry.

It has the exact same hardness (10 on Mohs scale). In fact, high-quality HPHT crystals can sometimes be structurally superior to natural stones due to the lack of nitrogen impurities (Type IIa).

Yes. HPHT diamonds are real carbon crystals and conduct heat/electricity exactly like mined diamonds. They will verify as 'Diamond' on standard handheld testers. Only UV-spectroscopy labs (IGI/GIA) can distinguish origin.

HPHT technology is more mature for mass-producing small sizes (1mm-3mm) with consistent high color and clarity. CVD is inefficient for melee. 99% of the world's top-quality melee is HPHT.

Yes, almost all HPHT colorless diamonds are Type IIa, meaning they lack nitrogen impurities. This is the rarest category in natural diamonds (less than 2% of mined stones).

It's a process (usually HPHT annealing) used to whiten lower-color CVD diamonds. Kunlun's HPHT diamonds are 'As Grown' (No Post-Growth Treatment), ensuring the structural integrity remains pristine.

We source only high-grade CVD that requires minimal to no treatment. We strictly reject 'brown tint' CVD stones that appear hazy or muddy.

Poor quality HPHT may glow after UV exposure (phosphorescence). Kunlun Growth performs QC to reject stones with visible long-lasting phosphorescence.

Trace metallic catalyst (iron/nickel) residues can sometimes make HPHT stones slightly responsive to strong magnets. However, our gem-quality stones are cleaned and cut to minimize inclusions, making magnetism negligible.