Timeline (11-42 Days)

Black Jack® Memory · CVD Science & Timeline

How a Memory Diamond Grows.

Black Jack Memory Diamonds are laboratory-grown diamonds. For CVD production, diamond crystal grows on a diamond seed inside a controlled low-pressure reactor using a hydrogen-rich carbon-containing gas and plasma energy.

The personal-carbon workflow and the CVD crystal-growth stage are related but scientifically distinct. Hair or cremation ashes are not simply placed inside the CVD reactor.

Diamond Seed Hydrogen + Carbon-Bearing Gas Microwave Plasma Layer-by-Layer Crystal Growth
Scientific Overview
Microwave Plasma CVD
CVD
H₂ + carbon-containing gas
such as CH₄ ↓



vacuum / exhaust →
single-crystal diamond seed / substrate
Low Pressure Vacuum reactor environment
~700–1200°C Process-dependent seed temperature range reported by GIA literature
Multi-Day Cycles Growth may stop for inspection / surface preparation
Important scientific clarification: Standard CVD is a gas-phase deposition process. A diamond seed is placed in the reactor and carbon-bearing gas—commonly methane diluted in hydrogen—is activated by plasma. Reactive carbon species deposit on the diamond seed and extend its crystal lattice. Where a documented personal-carbon contribution is used for a Memory Diamond, that contribution is handled upstream under the applicable laboratory preparation protocol; hair, ashes or a piece of solid purified carbon are not simply placed next to the seed.

Documented Production Flow

From personal sample to finished laboratory-grown diamond.

The ranges below are planning estimates, not universal laws of CVD growth. Some stages can overlap and an order can require repeat growth or inspection cycles.

01

Sample Receipt, Verification & Logging

Approx. 1 Business Day

The approved personal source arrives at the designated facility and is matched to the order under its unique Carbon Sample ID.

  • Package and order reference matched
  • Sample condition checked
  • Traceability record established
02

Personal-Carbon Preparation & Purification

Order / Lab Dependent

Eligible source material is processed through the applicable laboratory workflow to isolate and purify usable carbon and to prepare the documented personal-carbon contribution for the production protocol.

  • Hair/ashes are an upstream source—not the CVD growth substrate
  • Contaminants and non-carbon material are separated as required
  • Exact preparation method is laboratory/process specific
03

Diamond Seed & Reactor Preparation

Approx. 1–3 Business Days

A suitable single-crystal diamond seed is cleaned and positioned on the substrate stage. The reactor is prepared for the target growth recipe.

  • Diamond seed selected for growth geometry
  • Seed surface prepared and inspected
  • Vacuum chamber and growth conditions stabilized
04

Microwave Plasma CVD Diamond Growth

Often Multiple Weeks

Hydrogen-rich gas and a carbon-containing precursor such as methane flow through the low-pressure chamber. Microwave energy creates a plasma that breaks the gas into reactive species. Carbon-bearing species reach the hot seed surface and extend the diamond crystal layer by layer.

  • Hydrogen-rich gas chemistry favors diamond growth over non-diamond carbon
  • Seed/substrate temperature is commonly in roughly the 700–1200°C range depending on reactor and recipe
  • Growth can include stop/start cycles for inspection or surface preparation
  • GIA describes gem-CVD growth runs that can take roughly three to four weeks
05

Post-Growth Crystal Review

Approx. 1–3 Business Days

The as-grown crystal is removed and reviewed for usable dimensions, growth quality and the planned final cut.

  • Crystal dimensions and growth morphology reviewed
  • Defects / inclusions considered during planning
  • Additional growth may be scheduled if more usable rough is required
  • Any post-growth treatment, if used, should be disclosed where applicable
06

Laser Planning, Cutting & Polishing

Approx. 3–7 Business Days

The rough crystal is planned for the selected shape and expected yield, then laser-cut, faceted and polished.

  • Final carat depends on the entire rough crystal—not thickness alone
  • Shape, inclusions, proportions and yield affect finished weight
  • Symmetry, polish and appearance are checked after finishing
07

Quality Review, Certificate & Verification

Approx. 1–5 Business Days

Black Jack prepares the applicable authenticity documentation and final specification record linked to the order/reference.

  • Black Jack Brand Authenticity Certificate
  • Online verification / PDF record
  • Optional independent grading may add additional processing time
08

Jewelry Setting, Final QC & Worldwide Dispatch

Order Dependent

A loose Memory Diamond can proceed to final packing. Jewelry orders require the selected mounting/setting, final inspection and secure dispatch.

  • Custom jewelry can add production time
  • Worldwide shipping time is separate from laboratory production
  • International customs and destination-carrier handling can affect delivery

Standard CVD Science

What actually happens inside the growth chamber.

CVD does not recreate Earth’s geological pressure. It grows diamond through controlled surface chemistry in a low-pressure gas environment.

The technique is called Chemical Vapor Deposition because the diamond is deposited from reactive chemical species formed from the vapor/gas phase.

Black Jack Service Timeline

Production time is not the same thing as CVD growth time.

A Memory Diamond order includes intake, personal-carbon preparation, reactor scheduling, crystal growth, finishing, documentation and—in jewelry orders—setting work.

Sample Order Specific

Production timing starts after the required sample is received and verified.

Laboratory Production Approx. 20–45 Business Days

Typical planning range after sample verification. Larger/special orders can require additional time.

External Grading Additional Time

Optional independent grading is separate from Black Jack’s brand documentation.

Worldwide Delivery Separate Transit

Shipping time depends on destination, carrier service and customs processing.

Why there is no “4 mm = 1 ct” timeline table: Vertical CVD growth thickness alone cannot predict the finished diamond weight. Finished carat is determined by the complete three-dimensional rough crystal, usable growth area, seed dimensions, crystal morphology, defects, target shape, proportions and cutting yield. A 1 ct round, 1 ct oval and 1 ct emerald cut do not require identical rough geometry.

Why Timelines Vary

Eight factors can change the completion date.

Target Rough Size

A larger usable crystal generally requires more deposited diamond material and/or additional growth cycles.

Final Shape & Yield

Round, oval, emerald, pear, heart and other shapes need different rough dimensions and cutting plans.

Growth Quality

Crystal morphology, inclusions, stress or non-diamond carbon can require review, surface preparation or regrowth.

Color / Treatment Requirement

If a post-growth treatment is used for a particular specification, it can add processing and QC time.

Reactor Scheduling

Custom memorial production must be assigned to appropriate laboratory equipment and growth cycles.

Cutting Complexity

Fancy shapes and high-yield planning can require additional mapping, laser work and polishing.

Jewelry Manufacturing

Custom rings, pendants, earrings and other settings add CAD, casting, setting and final QC stages.

Independent Grading / Shipping

Third-party grading, international carrier transit and customs are outside the actual crystal-growth time.

CVD Timeline FAQ

The science behind the timeline.

Is purified hair or ash carbon placed directly inside the CVD chamber?
Not as a piece of solid hair, ash or graphite next to the diamond seed. Standard CVD diamond growth is a gas-phase process. The reactor uses a carbon-containing gas, commonly methane in a hydrogen-rich environment. Where a personal-carbon contribution is used, it must be processed upstream under the applicable laboratory protocol into a form compatible with the production workflow.
What gas is normally used to grow a CVD diamond?
Gem-quality CVD commonly uses a hydrogen-rich gas mixture with a small amount of a carbon-containing hydrocarbon such as methane. Microwave plasma activates the gas chemistry needed for diamond deposition on the seed.
How hot is a CVD diamond reactor?
Conditions depend on the reactor and growth recipe. GIA literature describes gem-quality CVD substrate temperatures broadly around 700–1200°C, with its consumer process overview describing approximately 900–1200°C.
How long does the actual CVD growth stage take?
There is no universal fixed growth time. GIA describes gem-quality CVD production that may use repeated stop/start cycles and can require roughly three to four weeks. Commercial reactors and recipes can grow at different rates, so Black Jack treats growth time as order- and laboratory-dependent.
Does a larger carat always mean a fixed number of extra growth days?
No. Larger finished stones generally require more usable rough, but carat cannot be calculated from vertical thickness alone. Width, length, depth, seed size, growth morphology, defects, final shape and cutting yield all affect the result.
Can a CVD crystal be removed and put back into the reactor?
Yes. GIA describes CVD growth using repeated stop/start cycles in which crystals can be removed for surface work or inspection and then returned for additional growth.
Is a CVD Memory Diamond a mined diamond?
No. It is a laboratory-grown diamond. Black Jack uses the laboratory-grown designation to clearly distinguish it from a natural mined diamond.
Does the finished Memory Diamond contain DNA or intact ashes?
No such claim is made. The finished laboratory-grown diamond is crystalline carbon and is not represented as retaining biological tissue, DNA or intact physical remains.

Related Memory Diamond Guides

Follow the full documented workflow.

How Memory Diamonds Are Made→ Carbon Source Guide→ Packing & Security→ Scientific Process & Disclosure→ Certification & Authenticity→ Worldwide Shipping & Processing→

Timeline Support

Need an estimate for your specific carat, shape or jewelry design?

Contact Black Jack with the target carat, shape, color preference, loose-diamond or jewelry requirement and your country. Existing customers should include their Order ID and Carbon Sample ID.

The team can provide an order-specific production estimate without presenting a laboratory growth rate as a guaranteed universal timeline.

Ask About Your Timeline →