How are memorial diamonds made from hair?

Hair contains carbon in its keratin structure. The carbon is extracted, purified to at least 99.95%, converted into graphite, and used as feedstock for High Pressure High Temperature growth. At approximately 5.5 GPa and 1,450°C, carbon crystallises on a diamond seed over roughly 35 to 50 days. The finished lab-grown stone has the same diamond crystal structure and core physical, chemical and optical properties as a mined diamond.

What is HPHT technology?

HPHT stands for High Pressure High Temperature. A controlled growth cell typically operates at approximately 5.5 GPa and 1,450°C. Bio-carbon graphite dissolves in a metal catalyst and crystallises around a diamond seed. The resulting stone is a genuine lab-grown diamond, not a simulant.

What does One Guest, One Chamber mean?

Silmaril's One Guest, One Chamber protocol means every HPHT growth chamber contains material from only one individual — human or pet. Your loved one's carbon is never mixed with another customer's material. Each sample is assigned a unique Life-ID when received by Silmaril and tracked individually through every step of the process.

What colour and clarity will my memorial diamond be?

Silmaril targets VS clarity or better and colourless to near-colourless grades within the D–H range. VVS grades can occur, but every crystal grows individually and the final carat, colour and clarity are confirmed only after cutting and 4C grading.

Can I watch the process or visit the laboratory?

HPHT growth is completed by specialist lab partners in China, and laboratory tours are not available. Instead, your order can include Life-ID-tagged photo and video milestone records across sample collection, handover, growth, cutting, setting, and dispatch. Contact market@silmaril.co.nz if you have specific questions about your order's progress.

How Memorial Diamonds Are Made | The Process

How a Memorial Diamond
Is Made

A detailed guide to the seven-stage process that transforms carbon from a hair sample into a lab-grown diamond — coordinated through Silmaril, with specialist HPHT growth completed by our lab partners in China.

Process at a Glance

7 documented stages from sample intake to finished jewellery
~60 days to finished diamond; ~80 days customer delivery estimate
HPHT technology replicates natural diamond formation
Carbon purified to at least 99.95%, then converted to graphite
Typical growth conditions: 1,450°C and 5.5 GPa
One Guest, One Chamber — never mixed with another customer's material
Each sample assigned a unique biological Life-ID
Target VS clarity or better; D–H colour range
GIA / IGI certification available on request
Human and pet hair processed identically
Photo and video evidence pack tied to your Life-ID

Day 1 — You send the sample

Submit Your Hair Sample

Contact Silmaril to begin. Silmaril provides sample preparation and posting instructions before you send your hair sample.

You return approximately 10 grams of clean, dry human hair. For pet fur, Silmaril recommends approximately 20 grams where available to provide sufficient processing margin; the laboratory's technical requirement can be lower depending on sample condition and target carat. Saved locks, grooming clippings, freshly cut hair, or fur from a brush may be suitable.

Silmaril memorial diamond hair sample preparation instructions

Day 1 — Silmaril intake

Life-ID Assignment

The moment your sample is received by Silmaril, it is logged and assigned a unique biological Life-ID. This identifier accompanies your material through every subsequent stage, including transfer to our specialist HPHT lab partner in China, carbon extraction, growth, cutting, setting, and delivery.

Your hair is immediately placed in its own dedicated, labelled container. It will never share space with another person's or animal's material for the entire duration of the process.

Each stage of your order is documented with photos and milestone video where available, then tagged to your Life-ID — creating a visual chain of custody from intake through shipping handover, China lab growth, cutting, setting, and delivery.

Laboratory stages 02–03

Carbon Extraction & Purification

Hair is composed largely of keratin — a fibrous protein whose molecular structure is built on a carbon backbone. Through a controlled thermal and chemical process, we break down the keratin chains and isolate the carbon.

The extracted carbon undergoes multi-stage filtration, washing and high-temperature treatment until it reaches at least 99.95% purity. Spectroscopic verification checks the carbon before it proceeds to graphitization.

This stage is recorded as part of your evidence pack, so the transition from hair sample to purified carbon is traceable within your order record.

Carbon purification vial from hair — Silmaril NZ

Before HPHT growth

Graphitization

Purified amorphous carbon is converted into crystalline graphite under high temperature in a vacuum or inert atmosphere. This ordered graphite structure is the direct carbon feedstock used in HPHT diamond growth.

Graphitization is a critical quality checkpoint: incomplete conversion can reduce growth yield and contribute to inclusions or colour inconsistency.

Approximately 35–50 days — HPHT growth

HPHT Crystal Growth

The bio-carbon graphite is loaded into a dedicated High Pressure High Temperature growth cell operated by our specialist lab partner in China, together with a small diamond seed and a metal catalyst. Typical operating conditions are:

Temperature: approximately 1,450°C
Pressure: approximately 5.5 gigapascals

Under these conditions, graphite dissolves in the catalyst and carbon migrates along a controlled thermal gradient to the seed crystal, building the cubic diamond lattice. Growth typically takes 35–50 days depending on the target stone and operating conditions.

One chamber. One guest. Always. No other customer's material is processed in the chamber alongside your loved one's carbon. Lab handover, chamber loading, rough stone recovery, and milestone progress are included in the photo and video record where available.

HPHT diamond growth chamber laboratory — Silmaril

After growth

Cutting, Polishing & 4C Grading

The raw diamond is removed from the chamber — rough, unpolished, and already unmistakably a diamond. It is assessed for quality, then passed to a skilled lapidary for cutting and polishing.

After polishing, the stone is assessed using the standard 4Cs: carat, colour, clarity and cut. GIA or IGI gemological certification can be arranged on request at additional cost.

Rough memorial diamond before cutting and grading

Final stage

Jewellery Setting & Delivery

The graded stone is set into your chosen 18K gold design, inspected, packaged and prepared for insured delivery.

The completed jewellery piece — together with any returnable unused material — is returned to your New Zealand address. Silmaril's customer delivery estimate is approximately 80 days from receipt of a suitable sample, including international logistics and jewellery setting. Customs or carrier delays may extend this estimate.

Finished memorial diamond necklace — The Guardian by Silmaril

Why Hair Becomes a Diamond

Diamonds are pure carbon arranged in a cubic crystal structure. Hair is rich in keratin, a protein whose molecular backbone contains carbon in abundance. The two are connected at the elemental level.

After extraction and purification, the carbon is converted into graphite. Inside the HPHT growth cell, graphite dissolves in a metal catalyst and carbon crystallises on a diamond seed under a controlled thermal gradient.

The resulting lab-grown stone has the same cubic carbon crystal structure and core physical, chemical and optical properties as a mined diamond. Specialised gemological equipment can identify its laboratory growth origin.

1,450°C Growth temperature

5.5 GPa Chamber pressure

35–50 Growth days

99.95%+ Carbon purity

How a Memorial Diamond
Is Made

Process at a Glance