Physical Properties and Specifications

• Chemical Composition: Al2O3 (Aluminum Oxide)

• Hardness: 9 on the Mohs scale

• Crystal System: Trigonal

• Refractive Index: 1.76 – 1.77

• Specific Gravity: 3.95 – 4.03

• Pleochroism: Weak to moderate (visible in some specimens)

• Fluorescence: Generally inert, but some may fluoresce under UV light

• Cleavage/Fracture: Indistinct cleavage; conchoidal fracture

Color and Quality Classifications

Available Color Ranges

• Primary Hues: Blue, yellow, pink, green

• Secondary Modifications: Violet, orange, gray

• Tone and Saturation Ranges: Light to dark tones; vivid saturation is most desirable

• Premium Colors: Deep blue, royal blue, and padparadscha (pink-orange)

• Commercial Grades: Commercial-grade sapphires are typically lighter hues or have visible inclusions

Clarity Characteristics

• Typical Inclusion Types: Rutile, silk, and crystal inclusions

• Clarity Grading Standards: Graded from eye-visible to eye-clean

• Source-Specific Features: Different sources produce varying inclusions

• Eye-Clean Criteria: Must be free of inclusions visible to the naked eye

Source Locations and Material

• Historic Sources: Kashmir, Burma (Myanmar)

• Current Production: Sri Lanka, Madagascar, Thailand

• Source-Specific Characteristics: Each location yields unique color and clarity traits

• Production Trends: Increasing interest in ethically sourced sapphires