Birthstones & Gem Knowledge
Birthstones by Month
Traditionally, a birthstone is associated with each month of the year. For example, the birthstone for January is a garnet, while lucky babies born in April get a diamond as their birthstone.
The origin of birthstones is believed to date back to the breastplate of Aaron which contained twelve gemstones representing the twelve tribes of Israel. The current list dates back to 1912 with only one addition since then – the tanzanite was added to December.
June Pearl & Alexandrite
October Tourmaline & Opal
November Topaz & Citrine
December Tanzanite, Zircon & Turquoise
The most valuable gemstones are those that exhibit a pure color and only “slight” hues of other colors in addition to their primary color. For example, . sapphires range in hue from “slightly purplish-blue” to “slightly greenish-blue,” pink sapphires always range from “pink” to “slightly purplish-pink,” and rubies range from “slightly orangish-red” to “slightly purplish-red”. With the exception of opals, variation in a gemstone’s hue will be called out in the gemstone details on the product detail page.
Tone represents the depth of color, ranging from colorless to black. Gemstone tone is described as “light,” “medium-light,” “medium,” “medium-dark,” and “dark.” Gemstones with the most sought-after tones fall within the medium-light to medium-dark range.
Saturation, or color purity, refers to the degree to which the gem is free from brown or gray hues. The most desirable gemstones, which show little gray or brown, are often described as having “vivid” or “strong” color saturation. Generally, the levels of color saturation will not be called out in the product details because the gemstones in our jewelry are hand-selected for their vivid colors.
Because gemstones form under unique circumstances, each individual gemstone is comprised of a combination of trace minerals, which create a unique set of identifying marks or inclusions. Inclusions will not necessarily detract from the beauty or desirability of a colored gemstone.
What to Look For
When considering a colored gemstone’s clarity, you should measure your expectations against the standard for that variety of gemstone. Some varieties of colored gemstones, such as aquamarine, blue topaz, and citrine, have naturally fewer inclusions while other gemstones, such as emerald and ruby, tend to have a higher rate of acceptable inclusions.
Clarity is an important factor in comparing quality colored gemstones. Even opaque opals can have milky inclusions that will affect their iridescence and color play. In general, the best values are available in gemstones that are moderately included. Exceptional gemstones with few or no inclusions are available, but they can command extravagant prices.
Colored gemstones are generally cut to maximize the beauty of their color. To recognize quality in the cut of a gemstone, there are several points to consider.
What to Look For
A good cut showcases the gemstone’s color, diminishes its inclusions, and exhibits good overall symmetry and proportion. Because gemstone color can vary, there are no hard geometrical standards when it comes to maximizing brilliance or color. Gemstones, especially rarer ones, are sometimes cut for size without regard for their color. For example, when corundum varieties such as sapphire and ruby are cut for maximum weight rather than beauty, they may display banded colors or streaks.
In a gemstone with more saturated color, the best cut may be more shallow than average, permitting more light to penetrate the gemstone, while in a less saturated gem, the color may benefit from a deeper cut.
Look at the gemstone in the setting and ensure that all the facets are symmetrical. An asymmetrically-cut crown indicates a gemstone of low-quality. In all cases, a well-cut gemstone is symmetrical and reflects light evenly across the surface, and the polish is smooth, without any nicks or scratches. These are the characteristics that AB&L jewelers look for when selecting our gemstone jewelry.
Like diamonds, fine quality color gems usually have a table, crown, girdle, pavilion, and culet. Iridescent opals are one exception, and most often have a rounded cabochon cut.
The carat weight of a gemstone does not necessarily allow you to accurately envision the size of the gemstone. Different gemstones have different densities (mass per unit volume), so two gems that appear to be the same size may actually have very different weights. For example, a ruby is more dense than a diamond, so a 1-carat ruby will look smaller than a 1-carat diamond.
Always request the dimensions of a gemstone to ensure that the majority of the gemstone weight will be visible when set in the setting.
To help you envision the gemstone’s actual appearance, we at Asset Brokers & Loans in Midland, Michigan provide the diameter dimensions (for round) or length and width (for other shapes) of a given gemstone. You can even click the zoom button to see a closer look at any piece of gemstone jewelry.