Gemstone Information
How to Buy a Diamond
Diamond professionals use four factors to describe and classify diamonds - color, clarity, cut & carat weight. When taken together, they help in evaluating the finished diamonds you buy. That's why they are often called value factors. Learn about the 4 C's...
Judging Quality of Colored Gemstones
The appearance of a colored gem is a combination of many separate factors, each of which is related to, and affected by, the others. It is precisely the complexity of these intertwined relationships that has bedeviled all attempts to quantify quality. Learn more details...
Colored Gemstone Buying Guide Links
| Alexandrite | Alexandrite is the variety of chrysoberyl that displays a change-of-color from green to red. A distinct color change is the primary qualification for a chrysoberyl to be considered alexandrite. View buying guide... |
| Demantoid | Demantoid is the name given to the rich green variety of andradite garnet. The gem was first discovered in Russia and the name is derived from its diamond-like adamantine luster. View buying guide... |
| Jadeite | The term jade is used for two different minerals, jadeite and nephrite. Only jadeite has value as a gem material in and of itself. View buying guide... |
| Lapis Lazuli | Lapis lazuli is one of the oldest of all gems, with a history stretching back some 7000 years or more. This mineral is important not just as a gem, but also as a pigment, for ultramarine is produced from crushed lapis lazuli (this is why old paintings using ultramarine for their blue pigments never fade). View buying guide... |
| Padparadscha | Padparadscha sapphire is a special variety of gem corundum, featuring a delicate color that is a mixture of pink and orange – a marriage between ruby and yellow sapphire. View buying guide... |
| Peridot | Peridot is one of the prettiest of all green gems, occurring in a color that is the epitome of grass green. Interestingly enough, the name topaz may have initially been applied to peridot, for it is found on the island of Topazos (Zabargad) in the Red Sea. View buying guide... |
| Ruby | The term ruby is reserved for corundums of a red color, with other colors called sapphire. In Asia, pink corundums are also considered rubies. Outside of Asia, such gems are generally termed pink sapphires. View buying guide... |
| Sapphire | The term sapphire alone describes the blue variety of gem corundum. Other colors have a color prefix, i.e., yellow sapphire, green sapphire, etc. View buying guide... |
| Spessartite | The name spessartite (a.k.a. spessartine) is derived from Spessart, in N.W. Bavaria, Germany. Garnet is the name for a group of related mineral species. The gem garnets include Pyralspites (Pyrope, Almandine, Spessartite) and Ugrandites (Uvarovite, Grossular, Andradite). View buying guide... |
| Spinel | Throughout history, spinel has been confused with ruby. In part, this is because spinel is often found in the same deposits. Gem spinel is a magnesium aluminum oxide, while ruby (corundum) is an aluminum oxide. View buying guide... |
| Tanzanite | Tanzanite is the name given to the rich blue-violet variety of the epidote-group mineral, zoisite. The gem was first discovered in Tanzania in 1967 and was named after its country of its origin, Tanzania, by the famous New York jeweler, Louis Comfort Tiffany. View buying guide... |
| Topaz | Topaz is the name for the mineral species that is number 8 on Mohs’ scale of hardness. There is some uncertainty regarding the name. Some say it comes from the Sanskrit word meaning “fire.” Others link it to the Red Sea Island of Topazios (Zabargad or St. John’s Island), where peridot has been found. View buying guide... |
| Tourmaline | Tourmaline is the name for a group of related mineral species. In gemological practice, individual species names are not used. Instead all are simply termed “tourmaline.” The name is derived from the Sinhalese word “tourmali,” which means “mixed parcel.” View buying guide... |
| Tsavorite | Tsavorite is the name given to the rich green variety of grossular garnet. The gem was first discovered in Tanzania in 1967 by Campbell Bridges. In 1970, Bridges also discovered gem tsavorite in Kenya’s Taita/Taveta district. The name “tsavorite” was coined in 1974 by Campbell Bridges and Tiffany’s Henry Platt and is derived from Kenya’s Tsavo National Park, which lies adjacent to rich deposits of the gem. View buying guide... |
The term "enhancement" is defined as any treatment or process other than cutting and polishing that improves the appearance (color/clarity/phenomena), durability, value or availability of a gemstone. In today's gem marketplace, many gemstones have been enhanced by a variety of methods. Such processes may range from simple heating (such as with tanzanite) to high-tech irradiation (such as blue topaz). Learn more details...
These gemstones were officially adopted in 1912 and are considered the accepted birthstone list in the U.S.
|
January February March April May June July August September October November December |
Garnet Amethyst Aquamarine or Bloodstone Diamond Emerald or Green Jade Pearl, Moonstone, or Alexandrite Ruby Peridot or Sardonyx Sapphire Opal or Pink Tourmaline Yellow Topaz or Citrine Tanzanite, Turquoise or Blue Zircon (Blue Topaz is a frequent substitute) |
Before the modern 12-month calendar was invented, astrologers assigned certain gemstones to the 12 signs of the zodiac based on the symbolism and metaphysical powers each stone was believed to possess.
| Capricorn Aquarius Pisces Aries Taurus Gemini Cancer Leo Virgo Libra Scorpio Sagittarius |
Dec 22-Jan 20 Jan 21-Feb21 Feb 22-Mar 21 Mar 22-Apr 20 Apr 21-May 21 May 22-June21 June 22-July 22 July 23-Aug 22 Aug 23-Sept 22 Sept 23-Oct23 Oct 24-Nov 21 Nov 22-Dec 21 |
Ruby Garnet Amethyst Bloodstone Sapphire Agate Emerald Onyx Carnelian Peridot Beryl Topaz |
The following list of anniversary stones combines information from the
- Gemological Institute of America,
- American Gem Trade Association,
- American Gem Society, and
- Jewelers of America.
If you need information for anniversaries not contained in this list, let us know and we will see what we can do to help.
Year12 3 4 5 6 7 8 9 10 |
GemGold JewelryRed Garnet Pearls Blue Topaz Sapphire Amethyst Onyx Tourmaline Lapis Lazuli Diamond |
Year1112 13 14 15 16 17 18 19 20 |
GemTurquoiseJade Citrine Opal Ruby Peridot Watches Cat's Eye Aquamarine Emerald |
Year2530 35 40 45 50 55 60 65 70 75 |
GemSilver JubileePearl Jubilee Emerald Jubilee Ruby Jubilee Sapphire Jubilee Golden Jubilee Alexandrite Diamond Jubilee Blue Spinel Sapphire Jubilee Diamond Jubilee |