Loupewise

Caráter Óptico das Gemas — Tabela do Polariscópio

Caráter óptico de 132 espécies — 34 de refração simples, 75 de refração dupla e 23 agregados — com marcação ADR e birrefringência. Entre polarizadores cruzados, uma pedra SR permanece escura, uma DR clareia quatro vezes por volta e um agregado permanece claro. Agrupadas SR primeiro, depois uniaxiais, biaxiais e agregados.

Os nomes das gemas aparecem na forma comercial em inglês e levam à ficha detalhada de cada espécie (em inglês).

Insira sua leitura no Loupewise e o mecanismo reduz os candidatos automaticamente. O aplicativo está disponível em português.

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GemaCaráter ÓpticoADRBirrefringênciaIntervalo IR
Almandine GarnetSR✓—1.770–1.830
AmberSR✓—1.539–1.545
Black OpalSR——1.440–1.460
Black SpinelSR✓—1.712–1.730
Blue DiamondSR✓—2.417
Brown DiamondSR✓—2.417
Color-Change GarnetSR✓—1.740–1.765
Cubic ZirconiaSR✓—2.150–2.180
CupriteSR——2.849
Demantoid GarnetSR✓—1.880–1.895
DiamondSR✓—2.417
Fire OpalSR——1.370–1.470
FluoriteSR——1.432–1.436
Grossular GarnetSR✓—1.734–1.759
HackmaniteSR——1.483–1.487
HauyneSR——1.494–1.509
Hessonite GarnetSR✓—1.730–1.760
JetSR——1.640–1.680
Low-Type ZirconSR——1.780–1.815
Malaya / Umbalite GarnetSR✓—1.730–1.780
MoldaviteSR——1.480–1.510
ObsidianSR✓—1.480–1.510
OpalSR——1.370–1.470
Pink DiamondSR✓—2.417
Pyrope GarnetSR✓—1.730–1.760
Rhodolite GarnetSR✓—1.740–1.770
Spessartite GarnetSR✓—1.790–1.815
SphaleriteSR——2.369–2.371
SpinelSR✓—1.712–1.736
Star GarnetSR✓—1.770–1.830
Synthetic SpinelSR✓—1.725–1.728
Tsavorite GarnetSR✓—1.730–1.760
YAGSR——1.833
Yellow DiamondSR✓—2.417
AmethystUniaxial (+)—0.0091.544–1.553
AmetrineUniaxial (+)—0.0091.544–1.553
BenitoiteUniaxial (+)—0.0471.757–1.804
CassiteriteUniaxial (+)—0.0961.997–2.093
CinnabarUniaxial (+)—0.3512.905–3.256
CitrineUniaxial (+)—0.0091.544–1.553
MoissaniteUniaxial (+)—0.0432.648–2.691
PhenakiteUniaxial (+)—0.0161.654–1.670
PrasioliteUniaxial (+)—0.0091.544–1.553
Rock CrystalUniaxial (+)—0.0091.544–1.553
Rose QuartzUniaxial (+)—0.0091.544–1.553
Smoky QuartzUniaxial (+)—0.0091.544–1.553
ZirconUniaxial (+)—0.0591.925–1.984
ApatiteUniaxial (−)—0.0061.628–1.649
AquamarineUniaxial (−)—0.0061.577–1.583
CalciteUniaxial (−)—0.1721.486–1.658
Chrome TourmalineUniaxial (−)—0.0181.624–1.660
Color-Change SapphireUniaxial (−)—0.0081.762–1.770
EmeraldUniaxial (−)—0.0061.565–1.602
GosheniteUniaxial (−)—0.0061.577–1.583
Green TourmalineUniaxial (−)—0.0181.616–1.650
HeliodorUniaxial (−)—0.0061.568–1.580
HematiteUniaxial (−)—0.2802.940–3.220
IndicoliteUniaxial (−)—0.0181.624–1.644
MorganiteUniaxial (−)—0.0081.572–1.600
Padparadscha SapphireUniaxial (−)—0.0081.762–1.770
Paraiba TourmalineUniaxial (−)—0.0181.624–1.644
Pink SapphireUniaxial (−)—0.0081.762–1.770
Red BerylUniaxial (−)—0.0071.564–1.574
RhodochrositeUniaxial (−)—0.2201.600–1.820
RubelliteUniaxial (−)—0.0181.624–1.644
RubyUniaxial (−)—0.0081.762–1.770
SapphireUniaxial (−)—0.0081.762–1.770
ScapoliteUniaxial (−)—0.0201.540–1.572
Star RubyUniaxial (−)—0.0081.762–1.770
Star SapphireUniaxial (−)—0.0081.762–1.770
SugiliteUniaxial (−)—0.0021.607–1.610
Synthetic Color-Change CorundumUniaxial (−)—0.0081.762–1.770
TaaffeiteUniaxial (−)—0.0041.719–1.723
TourmalineUniaxial (−)—0.0201.624–1.644
Watermelon TourmalineUniaxial (−)—0.0181.616–1.650
White SapphireUniaxial (−)—0.0081.762–1.770
Yellow SapphireUniaxial (−)—0.0081.762–1.770
AlexandriteBiaxial (+)—0.0091.746–1.755
Cat's Eye ChrysoberylBiaxial (+)—0.0091.746–1.755
Chrome DiopsideBiaxial (+)—0.0301.664–1.730
ChrysoberylBiaxial (+)—0.0091.746–1.755
ClinohumiteBiaxial (+)—0.0281.625–1.675
DiasporeBiaxial (+)—0.0481.702–1.752
EnstatiteBiaxial (+)—0.0101.663–1.673
HiddeniteBiaxial (+)—0.0161.660–1.676
KunziteBiaxial (+)—0.0161.660–1.676
LabradoriteBiaxial (+)—0.0111.559–1.573
LarimarBiaxial (+)—0.0401.595–1.640
PeridotBiaxial (+)—0.0361.654–1.690
PrehniteBiaxial (+)—0.0301.611–1.665
RhodoniteBiaxial (+)—0.0141.716–1.752
SpheneBiaxial (+)—0.1001.843–2.110
Star DiopsideBiaxial (+)—0.0301.664–1.721
TanzaniteBiaxial (+)—0.0091.691–1.700
ThuliteBiaxial (+)—0.0091.691–1.704
TopazBiaxial (+)—0.0081.609–1.643
AmazoniteBiaxial (−)—0.0081.514–1.530
AndalusiteBiaxial (−)—0.0101.629–1.649
DanburiteBiaxial (−)—0.0061.627–1.636
GrandidieriteBiaxial (−)—0.0331.590–1.623
IoliteBiaxial (−)—0.0121.540–1.560
KornerupineBiaxial (−)—0.0131.660–1.699
KyaniteBiaxial (−)—0.0161.712–1.734
MalachiteBiaxial (−)—0.2541.655–1.909
MoonstoneBiaxial (−)—0.0081.518–1.526
Rainbow MoonstoneBiaxial (−)—0.0111.559–1.572
SinhaliteBiaxial (−)—0.0381.665–1.712
SunstoneBiaxial (−)—0.0101.537–1.572
VarisciteBiaxial (−)—0.0311.560–1.594
AgateAgregado——1.530–1.543
AventurineAgregado——1.544–1.553
BloodstoneAgregado——1.530–1.543
CarnelianAgregado——1.530–1.543
ChalcedonyAgregado——1.530–1.543
CharoiteAgregado——1.550–1.559
ChrysocollaAgregado——1.575–1.635
Chrysocolla ChalcedonyAgregado——1.530–1.543
ChrysopraseAgregado——1.530–1.543
CoralAgregado——1.486–1.658
Hawk's EyeAgregado——1.544–1.553
HowliteAgregado——1.583–1.608
IvoryAgregado——1.535–1.540
JadeiteAgregado——1.654–1.688
Lapis LazuliAgregado——1.500–1.670
NephriteAgregado——1.600–1.627
OnyxAgregado——1.530–1.543
PearlAgregado——1.520–1.690
PietersiteAgregado——1.534–1.540
SerpentineAgregado——1.560–1.571
SodaliteAgregado——1.483–1.487
Tiger's EyeAgregado——1.544–1.553
TurquoiseAgregado——1.610–1.650

Quais gemas mostram dupla refração anômala (ADR)?
22 espécies desta tabela levam a marcação ADR, sobretudo as granadas e o diamante. Uma pedra SR tensionada pode mostrar extinção irregular que imita o piscar DR: confirme no refratômetro antes de descartar candidatas SR.

O diamante é de refração simples ou dupla?
De refração simples (sistema cúbico), mas marcado como ADR: a tensão interna produz com muita frequência extinção anômala no polariscópio. Essa combinação é, por si só, característica do diamante.

O que significam uniaxial e biaxial?
Pedras uniaxiais (tetragonal, hexagonal, trigonal: quartzo, coríndon, turmalina) têm um eixo óptico; biaxiais (ortorrômbico, monoclínico, triclínico: topázio, peridoto, tanzanita) têm dois.Cada uma leva um sinal, + ou −.

Veja também: Reference Database (EN) · Guide (EN)