Serpentine, nephrite jade and jadeite jade are both commonly referred to as "jade," but they are different minerals with distinct properties. Here’s a detailed comparison and identification guide: Jade Comparison and Identification Guide
1. Composition and Structure:
Serpentine and Nephrite Jade
Composition: Nephrite is a variety of the amphibole group, mainly composed of actinolite and tremolite.
Structure: It has a fibrous, interlocking structure, which contributes to its toughness.
Jadeite Jade
Composition: Jadeite is a pyroxene mineral, composed primarily of sodium and aluminum silicate.
Structure: It has a granular, crystalline structure, which is different from the fibrous nature of nephrite.
2. Color:
Serpentine and Nephrite Jade
Color Range: Commonly green, but can also be white, yellow, brown, or black.
Common Shades: Often exhibits more subdued, darker greens and can sometimes be mottled.
Jadeite Jade
Color Range: More varied, including green, white, lavender, yellow, pink, red, orange, blue, black, and gray.
Common Shades: Known for its vibrant, emerald-green variety (Imperial Jade), as well as other bright and varied colors.
3. Hardness:
Serpentine and Nephrite Jade
Mohs Hardness: Typically around 6 to 6.5.
Jadeite Jade
Mohs Hardness: Slightly harder, around 6.5 to 7.
4. Transparency:
Serpentine and Nephrite Jade
Transparency: Typically opaque, though high-quality nephrite can be translucent.
Jadeite Jade
Transparency: Ranges from opaque to semi-transparent, with high-quality jadeite being more translucent.
5. Density:
Serpentine and Nephrite Jade
Specific Gravity: Lower, typically around 2.90 to 3.03.
Jadeite Jade
Specific Gravity: Higher, around 3.30 to 3.38.
6. Luster:
Serpentine and Nephrite Jade
Luster: Waxy to silky.
Jadeite Jade
Luster: Vitreous to oily.
Identification Techniques:
- Visual Inspection:
- Color and Texture: Jadeite often has a more vibrant color and granular texture.
- Surface Luster: Jadeite has a glassier luster compared to nephrite.
- Hardness Test: Perform a scratch test to compare hardness.
- Specific Gravity Test: Measure density to distinguish between the two.
- Transparency Check: Check translucency under light.
- Professional Gemological Testing: Use refractometer, spectroscope, and X-ray diffraction for precise identification.
Summary:
- Serpentine and Nephrite Jade: Fibrous, tough, generally opaque, waxy luster, lower specific gravity.
- Jadeite Jade: Granular, slightly harder, can be semi-transparent, vitreous luster, higher specific gravity.
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