Amazonite
Last updated: April 2026
Blue-green microcline feldspar colored by lead and water; frequently sold as a turquoise alternative. Under magnification, whitish cross-hatch or grid twinning (perthitic albite intergrowth) is visible in most specimens and is a key field indicator. Distinguished from turquoise by lower RI and SG; from chrysoprase by higher RI; from jade by lower RI/SG and cleavage.
Physical & Optical Properties
RI Range1.514–1.530
SG Range2.54–2.58
SG Typical2.56
Hardness (Mohs)6–6.5
Crystal SystemTriclinic
Optic CharacterDR Biaxial (−)
Birefringence0.008
Dispersion0.012
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismWeak
ColorsGreen, Blue Violet
SpeciesFeldspar
VarietyMicrocline
Related: Feldspar Varieties
Key Differentiators
- Whitish cross-hatch twinning (perthitic grid) visible under magnification — diagnostic
- Low RI (1.514–1.530) separates from turquoise (RI 1.61–1.65) and jade
- Feldspar SG (~2.56) — lower than turquoise (~2.60–2.85)
Common Simulants
- Turquoise: Turquoise: RI 1.61–1.65; SG 2.60–2.85. Much higher RI and SG than amazonite. Matrix pattern differs; no cross-hatch twinning.
- Chrysoprase (chalcedony): Chrysoprase: RI ~1.535; SG ~2.58–2.61; microcrystalline aggregate; no twinning pattern. Usually more translucent than amazonite.
- Jadeite: Jadeite: RI 1.660–1.680; SG 3.24–3.43. Much higher RI and SG. Interlocking granular texture, not perthitic twinning.
Treatments
- Waxing / impregnation — surface stabilization
Price Context
Natural — low ($/ct)$5
Natural — high ($/ct)$50
NotePer carat; intense even blue-green with minimal white veining most prized; Colorado (USA), Russia, Madagascar material
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
Measurement Guides
Identifying an amazonite? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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