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Showing posts with label gemology. Show all posts
Showing posts with label gemology. Show all posts

Thursday, September 11, 2025

Dark Micro-Inclusions Create Star Patterns In Two Rare Diamonds | GIA Study

GIA examines two diamonds with star-shaped patterns from dark micro-inclusions. Learn about graphite clouds, hydrogen inclusions, and unique formation processes in natural diamonds.

Two Rare Diamonds Show Star-Shaped Patterns from Dark Micro-Inclusions

The Gemological Institute of America discovered something special. Two diamonds arrived at their lab with star-shaped patterns created by dark micro-inclusions.

These weren't ordinary diamonds. Each stone told a different story about how nature creates these patterns deep underground.

The First Diamond: Graphite Creates Six-Point Star

A 3.45-carat diamond from Zimbabwe caught researchers' attention immediately.

The stone showed these features:

  • Six lobed sectors forming a star pattern
  • Six-sided pattern in the center
  • Rough surfaces preserved along the edges
  • Graphite inclusions creating the star shape

What made this diamond special? The graphitic clouds radiated outward from the central figure. GIA researchers had never seen this pattern before.

You might wonder how graphite ends up inside diamonds. During formation, carbon particles can become trapped. Some form of diamond crystal structure. Others remain as graphite inclusions.

The Second Diamond: Hydrogen Clouds with Green Fluorescence

The second stone weighed 13.89 carats and showed different characteristics.

This diamond contained:

  • Dark clouds of micro-inclusions
  • Clear openings in the center of main facets
  • Hydrogen clouds causing the inclusions
  • Nickel-related elements
  • Green fluorescence under long-wave UV light

The green glow came from nickel-related peaks within the hydrogen clouds. When you expose this diamond to UV light, these areas fluoresce bright green.

Etch channels passed through the clear openings. These channels likely formed when radioactive fluids entered the stone while it was still underground.

Why These Patterns Form

Natural diamond formation involves extreme conditions. High pressure and temperature create the perfect environment for inclusions.

Several factors contribute to these patterns:

  • Fluid movement during formation
  • Temperature variations
  • Pressure changes
  • Chemical composition of surrounding rock
  • Time spent underground

Each diamond experiences unique conditions. This explains why no two inclusion patterns look identical.

What This Means for Diamond Identification

These discoveries help gemologists understand diamond formation better.

Both diamonds shared similar characteristics:

  • Infrared spectra patterns
  • Radiation staining
  • Dark micro-inclusions present

Yet each stone expressed these features differently. This variation helps experts identify natural diamonds from synthetic ones.

Natural diamonds carry their formation history within their structure. Synthetic diamonds lack this complex inclusion story.

The Science Behind Star Patterns

Star patterns in diamonds aren't completely unusual. Triangle and star shapes appear when you view inclusions through polished windows.

But these two diamonds showed something different. The radiating cloud patterns extended beyond typical formations.

The Zimbabwe diamond's graphite clouds created an asteriated effect. This means the star pattern appeared to have rays extending outward.

The larger diamond's hydrogen clouds formed around clear spaces. This created a negative space pattern rather than solid inclusions.

Future Research Implications

These discoveries open new research directions for gemologists.

Understanding inclusion patterns helps with:

  • Diamond origin determination
  • Formation process mapping
  • Natural vs synthetic identification
  • Age estimation methods
  • Mining location identification

Each new pattern adds to the gemological database. This helps researchers identify diamonds from specific regions or formation periods.

What Makes Each Diamond Unique

GIA researchers emphasized an important point. All natural diamonds have their own formation journey.

No two stones follow identical paths from carbon to crystal. Environmental factors create unique signatures in each diamond.

These signatures include:

  • Inclusion types and patterns
  • Trace element composition
  • Crystal structure variations
  • Surface characteristics
  • Internal stress patterns

Think of inclusions as fingerprints. Each pattern tells you about the diamond's underground experience.

Practical Applications

These research findings benefit several groups:

Jewelers and appraisers can better identify natural diamonds and understand their characteristics.

Collectors gain insight into rare inclusion patterns and their significance.

Researchers expand their knowledge of diamond formation processes.

Consumers learn what makes their diamonds truly unique, natural creations.

The Journey Continues

Diamond research continues to reveal new patterns and formation processes. Each discovery adds another piece to the puzzle of how these crystals form.

The two diamonds studied by GIA represent just a small sample of natural variation. Thousands more diamonds with unique patterns wait to be discovered and studied.

Your diamond likely contains its own unique story written in inclusions and crystal patterns. These microscopic features connect your jewelry to billion-year-old geological processes.

Understanding these patterns helps you appreciate the natural forces that created your diamond's individual characteristics.


Thursday, August 28, 2025

GIA Updates Lab-Grown Diamond Grading: What You Need To Know

GIA will introduce a new grading system for lab-grown diamonds from Oct. 1. Learn how “premium” and “standard” classifications work, fees, and submission rules.

GIA has announced major changes to its grading system for lab-grown diamonds. The update takes effect on October 1.

Why the change?
According to GIA’s president and CEO, Pritesh Patel, most lab-grown diamonds fall into a narrow range of quality. Using the same terms as natural diamonds no longer makes sense.

From October, lab-grown diamonds in the D–Z color range will be classified as either premium or standard.

Premium Criteria

To be graded as premium, a lab-grown diamond must meet all of these:

  • Clarity: Very, very slightly included (VVS) or higher

  • Color: D

  • Polish: Excellent

  • Symmetry: Excellent

  • Cut (round brilliant only): Excellent

Standard Criteria

A lab-grown diamond will be classified as standard if it meets these:

  • Clarity: Very slightly included (VS)

  • Color: E to J

  • Polish: Very good

  • Symmetry: Very good (good allowed for fancy shapes)

  • Cut (round brilliant only): Very good

Diamonds that don’t meet at least the standard level will not receive a grading.

Fees and Submission Details

  • Assessment fee: $15 per carat (minimum $15)

  • Non-qualifying stones: $5 evaluation fee

  • Minimum weight: 0.15 carat

  • Inscription: Each stone will be laser-marked with “laboratory-grown” and a GIA quality number

  • Document: Printed evaluation results will be provided

What This Means for You

If you deal in lab-grown diamonds, this change will directly affect your inventory.

  • Do your stones qualify as premium or standard?

  • Will customers see more value in a premium grade?

  • How will this impact pricing in your market?

The new GIA system could shift how buyers compare lab-grown diamonds with natural ones. As a seller, you may need to rethink how you present and price your stones.

GIA is changing how it grades lab-grown diamonds. Starting Oct. 1, stones will be classified as either premium or standard instead of using natural diamond terms. Premium requires the highest grades in clarity, color, cut, polish, and symmetry. Standard covers a wider range. Diamonds below standard will not be graded. Fees start at $15 per carat.

Thursday, April 21, 2022

Gem-A GemIntro

An online only, entry-level course by The Gemmological Association of Great Britain.


Useful link: https://gemintro.gem-a.com

Tuesday, April 13, 2021

What Can You Do With Your Gemology?

The Accredited Gemologists Association is launching a forum called What Can You Do With Your Gemology? The online bi-annual event, free and open to all, is designed to showcase the variety of applications for gemological accreditation and career paths to consider. 


Useful link: https://accreditedgemologists.org

Thursday, October 24, 2019

Thursday, September 26, 2019

Thursday, July 11, 2019

Thursday, April 11, 2019

CIBJO Congress 2019

CIBJO, the World Jewellery Confederation, will hold its 2019 annual congress in Manama, the capital of the Kingdom of Bahrain, from November 18 to November 20. Pre-congress meetings will be held November 16 and 17, and the congress will follow the World Pearl Forum, which is due to take place on November 14 and 15. The CIBJO Annual Congress will be organised by DANAT, the Bahrain Institute for Pearls and Gemstones, which is dedicated to developing the local and regional pearl and gemstone industry, and operates one of the world’s most sophisticated laboratories in the field.

The official venue and hotel of the 2019 CIBJO Congress is the Four Seasons Hotel Bahrain Bay. Jewelers and gemologists: Mark your calendar!