Unlike the randomness of natural gemstones, our lab-grown gems are produced under a standardized control system to ensure consistency between batches.

During the crystal growth stage, we continuously monitor and control key parameters, and by standardizing the parameter system, we ensure the stability of the crystal structure.

How We Control Quality

100% Inspection / Batch Traceability

Raw material control

High-purity raw materials (4N–5N grade) undergo batch-by-batch re-inspection prior to warehousing, covering chemical purity, particle size distribution, and moisture and impurity content. A unique batch-number traceability system is established to ensure that every gemstone can be traced back to its original raw material batch.

End-to-end data recording

Growth process monitoring

Temperature profiles, diameter variations, and pressure data are automatically recorded throughout the process; immediate audio-visual alarms are triggered by abnormal conditions, which also automatically initiate a protective shutdown. The morphology of the solid-liquid interface is monitored in real-time via an online CCD system.

Key item: 100% full inspection

Quality Inspection for Cutting and Grinding Processes

After the raw crystals undergo directional cutting, shaping, and fine polishing, each piece is individually inspected for dimensional tolerances, surface flatness, surface finish, and angular precision of the facets. Leveraging a research-grade processing system inherited from the company's origins in laser crystal manufacturing, the surface finish meets nanometer-scale requirements (with Ra values ​​as low as a few nanometers)—far exceeding standard jewelry industry benchmarks; any non-conforming units are routed for rework or downgrading.

Multidimensional comprehensive grading

Finished Product Grading and Evaluation

Grading is conducted based on multiple dimensions, including color, clarity, transparency, cut, dimensions, crystal integrity, optical homogeneity, fluorescence characteristics, chemical composition, and synthetic identification markers.

Report / Compliance Disclosure

Factory Certification and Declarations

A testing report or specifications certificate is issued for each gemstone or batch; in accordance with the GB/T 16552 national standard, the "Synthetic" (or "Lab-grown") status and any enhancement treatments are clearly indicated to safeguard consumers' right to information and ensure transaction transparency.

Regarding "Synthetic" Labeling: In accordance with the national recommended standard GB/T 16552-2017 (*Jewelry and Jade – Nomenclature*), all lab-grown gemstones must be clearly labeled at the point of sale as "Synthetic [Material Name]" (e.g., "Synthetic Corundum," "Synthetic Spinel") or with equivalent terms (such as "Lab-created" or "Laboratory-grown"). LGPG guarantees that all products are labeled in 100% compliance with these standards and strictly prohibits the sale of lab-grown gemstones as natural gemstones.

Core Tests and Methods

  • Color Quality Assessment

    Visual color comparison (D65 standard light source) and UV-Vis spectrophotometry are used to record chromaticity coordinates, hue, saturation, and uniformity, and to distinguish between natural coloration and artificial coloring.

  • Observation of Clarity and Inclusions

    Using an optical microscope at 40–60× magnification under dark-field or bright-field illumination, observe the type, quantity, size, location, and distribution of inclusions, and distinguish between natural inclusions and those characteristic of the growth process.

  • Cut and Manufacturing Quality

    Microscope + proportion meter checks parameters such as symmetry, polishing quality, facet angle deviation and table width ratio.

  • Surface Finish Testing

    An optical profilometer is used to measure the Ra roughness of the polished surface; leveraging the research-grade polishing processes originally developed for laser crystals, the surface figure accuracy is required to be at the nanometer level—far exceeding standard jewelry processing benchmarks.

Testing instruments

  • Polarizing Microscope

    Optical characteristics, internal stress

  • XRD

    Variety verification and crystal orientation determination

  • Optical Microscopy

    Clarity grading, identification of inclusions

  • UV-Vis Spectrophotometer

    Color quality assessment, quantification of dopants

  • Optical Profiler

    Surface finish testing

Factory Standard

  • Clear color grading

    The color grade is clear and complies with established color standards to ensure stable and consistent color.

  • Passed visual inspection

    The surface is complete without obvious defects, and the cut, shape and overall presentation meet the requirements.

  • The dimensions are within the tolerance range.

    Dimensions are strictly controlled within the permissible tolerance range to ensure uniform specifications.

  • Clarity

    The clarity has been professionally verified and meets the requirements for the corresponding quality grade.