The Modern Diamond Landscape

Laboratory-grown diamonds (LGDs) have become a major presence in today's fine jewellery industry. Because both natural and lab-created diamonds are composed of pure crystallized carbon in an isometric lattice, they exhibit identical refractive index (2.417), hardness (10 on Mohs scale), and thermal conductivity.

Standard handheld thermal diamond testers cannot distinguish between them. Determining whether a stone was formed over billions of years in the Earth's mantle or synthesized in a laboratory reactor requires advanced gemological laboratory equipment.

Growth Technologies: HPHT vs. CVD

There are two primary methods used to create gem-quality diamonds in laboratories:

• High Pressure High Temperature (HPHT): Replicates the extreme tectonic environment of the Earth (up to 60,000 atmospheres and 1,500°C) using cubic or belt presses.
• Chemical Vapor Deposition (CVD): Uses a carbon-rich plasma gas (such as methane and hydrogen) inside a vacuum chamber to deposit carbon atoms layer-by-layer onto a diamond seed crystal.

How Gemological Laboratories Verify Origin

Professional gemological institutes like GGDL employ multi-tiered testing protocols to deliver 100% conclusive identification:

1. Fourier-Transform Infrared Spectroscopy (FTIR): Determines diamond type (Type Ia, Ib, IIa, IIb). Over 98% of natural diamonds are Type Ia (containing aggregated nitrogen), whereas most lab-grown diamonds are Type IIa (near-zero nitrogen).

2. Deep UV Luminescence Imaging: Analyzes growth morphology. Natural diamonds show octahedral growth sectors, HPHT stones exhibit geometric cross patterns, and CVD stones reveal planar dislocation striations.

3. Photoluminescence (PL) Spectroscopy at Cryogenic Temperatures: Detects atomic-level lattice defects, silicon-vacancy centers (SiV-), and catalyst metal trace residues (like nickel or iron).