WoW! Junior Gemologist
Birth Stones
by Donald Clark CSM
MONTH | MODERN | ANCIENT |
|---|---|---|
| January | Garnet | Garnet |
| February | Amethyst | Amethyst |
| March | Aquamarine | Bloodstone |
| April | Diamond | Diamond |
| May | Emerald | Emerald |
| June | Alexandrite | Pearl |
| July | Ruby | Ruby |
| August | Peridot | Sardonyx |
| September | Sapphire | Sapphire |
| October | Rose Zircon | Tourmaline or Opal |
| November | Golden Topaz | Topaz |
| December | Blue Zircon | Turquoise or Lapis |
... Gems have poetic and romantic meanings to people. Probably the best known example of this is our use of birthstones. For people born in any month, a special stone is assigned to them. It is often believed to be their "good luck" stone. Mothers have rings made with the birthstone of each family member.
... Which stone goes with a month varies with different cultures. This list is for English speaking countries.
... As you can see, it has changed. The modern list was created about a century ago. The ancient list is still used. The modern list has not replaced the ancient one, but has supplemented it. People are free to choose whichever stone they are most comfortable with.
... Our Junior Gemologist Program will focus on the twelve ancient birthstones. These stones have all the properties a person is likely to encounter.
... All the gems are minerals, except for pearls.
... Minerals are created in the earth. Pearls are considered "organic" because they are created in a living organism, an oyster. Another example of an organic gem is amber. Amber began life as tree sap. After millions of years it became fossilized into the gem we know today.
2 Which of these stones are usually cut as a cabochon?
... Bloodstone, Sardonyx, Opal, Turquoise and Lapis.
... Except for pearls, which are never cut, all the other birthstones can be cut as a cabochon. However, the transparent ones, (garnet, amethyst, diamond, emerald, ruby, sapphire, tourmaline and topaz,) are best known as faceted gems.
... Cutting En Cabochon, or as it is more commonly known, cutting cabs, is the most common form of gem cutting. Cabs are gems that are cut with a flat bottom and a curved or domed top. (See the picture of the cabochon cut, amethyst to the right.) This method is used for opaque stones, or transparent ones with a lot of inclusions.
... Faceting is a style of cutting that is used on transparent stones. If you can envision a diamond, you are looking at a faceted gem. The surface of a diamond is covered with
several geometrically arranged, flat surfaces. Each of these flat surfaces is called a facet. The gem is faceted, by a faceter on a faceting machine. This is also where we get the expression, "a multifaceted question."
... The purpose of faceting is to bring out the brilliance of a gem. That is where the light entering the stone is reflected from inside the gem, back to the viewer. Brilliance should not be confused with fire, which is the multicolored flashes you see coming out of diamonds and some other gems.
3 Which of these stones are the most valuable?
... Diamond, Emerald, Ruby and Sapphire.
... A common question is "What gem is the most valuable?" There is no simple answer to that. The value of a gem depends on four qualities, which are frequently known as the Four C's.
... Color. Gems are not created equal and the richer the color, the higher the value. With diamonds, the closer they are to being colorless, the higher they are in value.
... Clarity. If a gem is completely transparent, it will be worth more than one that is hazy. All gems have inclusions, which means things inside of them. These can be cracks or bits of other minerals. Some are so small they can't be seen and have little or no effect on the value. Others are big and ugly!
... Carat. This is the gems size. Big gems are more rare than little ones.
... Cut. How well a gem is cut has a lot to do with its beauty.
... So, when you ask if a diamond is more valuable than an emerald or ruby, you have to take all these factors into consideration. Rubies that weigh over a carat are much rarer than diamonds in that size. A three carat ruby, with excellent color and clarity, can be worth more than a diamond the same size and clarity.
... Emeralds grow fairly large, so size isn't as important a consideration as with ruby. However, emeralds almost always have eye visible inclusions. A top colored diamond, with the same amount of inclusions as a top colored emerald, would have less value.
... How well a gem is cut has a lot to do with its beauty and value. If you had two gems, (a ruby and a diamond, or two diamonds,) and their color, cut and clarity gave them the same value, their cut would determine which is the most valuable.
... Just imagine a diamond that sparkles with fire and light! Next to it is one that looks dull, like a piece of cut glass. That is the difference in cutting!