Birthstones
"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.
| Month | Color | Modern | Traditional | Alternate |
|---|
| January | Brick Red | Garnet | Garnet | Rose Quartz |
| February | Purple | Amethyst | Amethyst | Black Onyz Moonstone |
| March | Seafoam Blue | Aquamarine | Bloodstone | Rock Crystal |
| April | Colorless | Diamond | Diamond | White Sapphire White Topaz |
| May | Green | Emerald | Emerald | Green Tourmaline Tsavorite Garnet |
| June | White | Pearl/Moonstone | Alexandrite | Opal |
| July | Red | Ruby | Ruby | Rubellite Tourmaline |
| August | Yellowish-Green | Peridot | Jade | Star Sapphire |
| September | Royal Blue | Blue Sapphire | Blue Sapphire | Iolite Lapis Lazuli |
| October | Pink | Opal Pink Tourmaline | Jasper | Pink Sapphire Moganite |
| November | Golden Yellow | Golden Topaz Yellow Citrine | Yellow Citrine | Yellow Sapphire Tiger's Eye |
| December | Sky Blue | Blue Topaz or Turquoise | Blue Zircon Turquoise | Blue 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.
| Year | Gemstone | Year | Gemstone |
|---|
| 1st | Gold Jewelry | 2nd | Garnet |
| 3rd | Pearls | 4th | Blue Topaz |
| 5th | Blue Sapphire | 6th | Amethyst |
| 7th | Onyx | 8th | Green Tourmaline |
| 9th | Lapis Lazuli | 10th | Diamond Jewelry |
| 11th | Turquoise | 12th | Jade |
| 13th | Yellow Citrine | 14th | Opal |
| 15th | Ruby | 16th | Peridot |
| 17th | Watches | 18th | Cat's Eye Chrysoberyl |
| 19th | Aquamarine | 20th | Emerald |
| 21st | Iolite | 22nd | Spinel |
| 23rd | Imperial Topaz | 24th | Tanzanite |
| 25th | Silver Jubilee | 30th | Pearl Jubilee |
| 35th | Emerald | 40th | Ruby |
| 45th | Sapphire | 50th | Golden Jubilee |
| 55th | Alexandrite | 60th | Diamond Jubilee |
| 70th | Sapphire Jubilee | 80th | Ruby 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 Hardness | Mineral used for Comparison | Simple Hardness Tester | Cutting Hardness (A. Rosiwal) |
|---|
| 10 | Diamond | | 140,000.00 |
| 9 | Corundum | | 1,000.00 |
| 8 | Topaz | | 175.00 |
| 7 | Quartz | Scratches window glass | 120.00 |
| 6 | Orthoclase Feldspar | Can be scratched with a steel file | 37.00 |
| 5 | Apatite | Can be scratched with a knife | 6.50 |
| 4 | Fluorite | Can be easily scratched with a knife | 5.00 |
| 3 | Calcite | Can be scratched with a copper coin | 4.50 |
| 2 | Gypsum | Can be scratched with a fingernail | 1.25 |
| 1 | Talc | Can be scratched with a fingernail | 0.03 |
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.