Gemological Resources
Access our comprehensive collection of gemstone data, research papers, tutorials, and educational materials to enhance your gemological knowledge.
Gemstone Database
Search through 500+ gemstone varieties with complete optical properties and identification guides.
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Research Papers
Read our latest research on gemological analysis techniques and AI applications.
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Video Tutorials
Learn gemstone identification techniques through our comprehensive video series.
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Webinars
Join live sessions with expert gemologists and stay updated with industry trends.
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Gemstone Database
Our comprehensive database includes over 500 gemstone varieties with detailed optical properties, origin information, and identification characteristics.
Common Gemstones Reference
| Gemstone |
Category |
SG Range |
RI Range |
Hardness |
Key Identifiers |
| Diamond |
Precious |
3.52 |
2.42 |
10 |
Brilliance, dispersion |
| Ruby |
Corundum |
3.99-4.01 |
1.76-1.77 |
9 |
Silk inclusions, red fluorescence |
| Sapphire |
Corundum |
3.99-4.01 |
1.76-1.77 |
9 |
Color zoning, silk |
| Emerald |
Beryl |
2.70-2.78 |
1.57-1.58 |
7.5-8 |
Jardin inclusions, color |
| Topaz |
Topaz |
3.53-3.56 |
1.61-1.64 |
8 |
Perfect cleavage |
| Opal |
Opal |
2.15 |
1.45 |
5.5-6.5 |
Play-of-color |
| Amethyst |
Quartz |
2.65 |
1.54-1.55 |
7 |
Purple color, color zoning |
| Aquamarine |
Beryl |
2.68-2.74 |
1.57-1.58 |
7.5-8 |
Blue-green color |
| Peridot |
Olivine |
3.34 |
1.65-1.69 |
6.5-7 |
Double refraction |
| Garnet |
Garnet |
3.8-4.2 |
1.74-1.89 |
7-7.5 |
Isotropic, color varieties |
Gemstone Categories by Specific Gravity
- Very Light (<2.50): Opal (2.15), Amber (1.08)
- Light (2.50-3.00): Quartz (2.65), Beryl (2.70-2.78), Turquoise (2.60-2.80)
- Medium (3.00-3.50): Diamond (3.52), Topaz (3.53-3.56), Peridot (3.34)
- Heavy (3.50-4.00): Corundum (3.99-4.01), Garnet (3.8-4.2)
- Very Heavy (>4.00): Zircon (4.0-4.7), Hematite (5.0-5.3)
Refractive Index Ranges
- Low RI (1.40-1.60): Opal (1.45), Quartz (1.54-1.55), Beryl (1.57-1.58)
- Medium RI (1.60-1.80): Topaz (1.61-1.64), Peridot (1.65-1.69), Corundum (1.76-1.77)
- High RI (1.80-2.00): Garnet (1.74-1.89), Zircon (1.78-1.99)
- Very High RI (>2.00): Diamond (2.42), Cubic Zirconia (2.15-2.18)
Research Papers
AI-Powered Gemstone Identification: A Comparative Study
K.M.S. Chandrapala, Dr. J. Chen, S. Williams
Journal of Gemological Science, Vol. 45, 2025
This study compares traditional gemological identification methods with AI-powered computer vision techniques, demonstrating 99.9% accuracy in identifying 200+ gemstone varieties.
Inclusion Analysis in Natural vs. Synthetic Rubies
Dr. J. Chen, K.M.S. Chandrapala
Gems & Gemology, Winter 2025
A comprehensive analysis of inclusion patterns in natural and synthetic rubies, identifying key diagnostic features for gemological identification.
Digital Refractometry: New Methods for RI Measurement
S. Williams, Prof. M. Roberts
International Journal of Gemology, March 2026
This paper introduces novel computer vision techniques for measuring refractive index using standard camera equipment, achieving accuracy comparable to traditional refractometers.
Scratch Detection Algorithms for Gemological Applications
L. Thompson, K.M.S. Chandrapala
Computational Gemology, 2026
Development of machine learning algorithms for automated scratch detection on gemstone surfaces, with applications in quality grading and authentication.
Video Tutorials
Getting Started with Gem Scanning
Learn the basics of using our gem scanner for accurate identification.
12 min
5.2K views
Understanding Specific Gravity
Master the hydrostatic method for accurate SG measurements.
15 min
3.8K views
Refractive Index Testing
Learn how to measure and interpret refractive index values.
18 min
4.1K views
Ruby Identification Guide
Identify natural rubies by color, inclusions, and fluorescence.
22 min
6.7K views
Scratch Detection Techniques
Use 40x zoom to detect microscopic surface scratches.
10 min
2.9K views
Understanding Gem Treatments
Learn to identify heat treatment, diffusion, and filling.
25 min
4.5K views
Upcoming Webinars
March 15, 2026
Ruby Identification Masterclass
Dr. James Chen
10:00 AM - 12:00 PM (Sri Lanka Time)
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March 22, 2026
Diamond Grading Workshop
Prof. Michael Roberts
2:00 PM - 4:00 PM (Sri Lanka Time)
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April 5, 2026
Gemstone Treatment Detection
K.M.S. Chandrapala
10:00 AM - 12:00 PM (Sri Lanka Time)
Register Now →
Downloadable Resources
SG Reference Chart
Complete specific gravity reference for 200+ gemstones
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RI Reference Chart
Refractive index values for all major gemstones
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Gemstone Database
Complete database in Excel format
Download XLSX
Identification Flowchart
Step-by-step gemstone identification guide
Download PDF
Treatment Detection Guide
How to identify common gemstone treatments
Download PDF
Gemstone Glossary
Comprehensive gemological terminology
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Gemstone Glossary
Asterism
A star-like optical phenomenon displayed by some gemstones when cut en cabochon.
Birefringence
The difference between a gemstone's maximum and minimum refractive indices.
Chatoyancy
The cat's-eye effect caused by parallel inclusions reflecting light.
Dichroism
The property of showing two different colors when viewed from different directions.
Inclusion
Internal characteristics within a gemstone, often used to determine origin.
Pleochroism
The property of showing different colors in different crystal directions.
Refractive Index (RI)
The measure of how light bends when entering a gemstone.
Specific Gravity (SG)
The ratio of a gemstone's weight to the weight of an equal volume of water.
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