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Education - Gemstone Guide


"Modern" column: Birthstones listed are the Official Birthstone adopted by the American National Association of Jewelers, Jewelers of America. These Birthstones were officially adopted in 1912.

"Traditional" column: Contains older birthstones and is sometimes combined with the modern birthstone list. (Many jewelers have differing lists of Traditional Birthstones.)

"Alternate" column: Contains stones used by Gem Dealers and Jewelry Manufacturers as alternate birthstones for each month.

Gemstone Guide

JanuaryBrick RedGarnetGarnetRose Quartz
FebruaryPurpleAmethystAmethystBlack Onyz Moonstone
MarchSeafoam BlueAquamarineBloodstoneRock Crystal
AprilColorlessDiamondDiamondWhite Sapphire White Topaz
MayGreenEmeraldEmeraldGreen Tourmaline Tsavorite Garnet
JulyRedRubyRubyRubellite Tourmaline
AugustYellowish-GreenPeridotJadeStar Sapphire
SeptemberRoyal BlueBlue SapphireBlue SapphireIolite Lapis Lazuli
OctoberPinkOpal Pink TourmalineJasperPink Sapphire Moganite
NovemberGolden YellowGolden Topaz Yellow CitrineYellow CitrineYellow Sapphire Tiger's Eye
DecemberSky BlueBlue Topaz or TurquoiseBlue Zircon TurquoiseBlue Spinel Lapis Lazuli

Anniversary Gemstones

This list of suggested gemstone gifts is endorsed by the American Gem Trade Association, the American Gem Society, Jewelers of America, The Jewelry Industry Council, the Gemological Institute of America, and the Cultured Pearl Association of America.

1stGold Jewelry2ndGarnet
3rdPearls4thBlue Topaz
5thBlue Sapphire6thAmethyst
7thOnyx8thGreen Tourmaline
9thLapis Lazuli10thDiamond Jewelry
13thYellow Citrine14thOpal
17thWatches18thCat's Eye Chrysoberyl
23rdImperial Topaz24thTanzanite
25thSilver Jubilee30thPearl Jubilee
45thSapphire50thGolden Jubilee
55thAlexandrite60thDiamond Jubilee
70thSapphire Jubilee80thRuby Jubilee

Relative and Absolute Hardness Scale

In 1812 the MOH's scale of gem hardness was devised by German mineralogist Frederich Mohs (1773-1839). MOH's hardness is a relative scale. It shows which mineral scratches another mineral. The table below shows MOH's hardness in relation to Simple and Cutting Hardness. (Cutting hardness in water according to A. Rosiwal).

MOH's HardnessMineral used for ComparisonSimple Hardness TesterCutting Hardness (A. Rosiwal)
10Diamond 140,000.00
9Corundum 1,000.00
8Topaz 175.00
7QuartzScratches window glass120.00
6Orthoclase FeldsparCan be scratched with a steel file37.00
5ApatiteCan be scratched with a knife6.50
4FluoriteCan be easily scratched with a knife5.00
3CalciteCan be scratched with a copper coin4.50
2GypsumCan be scratched with a fingernail1.25
1TalcCan be scratched with a fingernail0.03

GIA Color Grades

Color Explanation of Colored Gemstones: The GIA "Color Stone Grading System" is made up of three main components, Hue, Tone and Saturation.

Hue is described as the shade, tint or sensation of a color: The GIA Gem Set has 31 Hues which can be used to describe virtually all colored gemstones. The complete GIA Gem Set includes 324 sample hue colors with varying Tones and Saturations.

Tone is described as the strength or purity of a Hue. The GIA Tone Scale is divided into 11 grades, 0 to 10, with 0 being colorless to 10 being black.

Saturation is described as the strength or purity of a Hue. The GIA Saturation Scale is from 1 to 6. The lower numbers such as 1, 2, or 3 of warm colors such as red, orange or yellow and tend to look brownish and the cool colors such as blue and green tend to look grayish. Level 4 no longer shows either grayness or brownness , while neither is strong or weak. Level 5 is strong and Level 6 being vivid, almost over colored.

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