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Gemstone Information

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. Read more about the 4 C's of buying a diamond or watch this video.

If you have a diamond that you're not sure is the real thing, watch this video to find out methods to find out for sure.

Green 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

Blue gemstones

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

Birthstones

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 Spinel
Sapphire
Opal or Pink Tourmaline
Yellow Topaz or Citrine
Tanzanite, Turquoise or Blue Zircon
(Blue Topaz is a frequent substitute)

January • Garnet
February • Amethyst
March • Aquamarine or Bloodstone
April • Diamond
May • Emerald or Green Jade
June • Pearl, Moonstone, or Alexandrite
July • Ruby
August • Peridot or Sardonyx
September • Sapphire
October • Opal or Pink Tourmaline
November • Yellow Topaz or Citrine
December • Tanzanite, Turquoise or Blue Zircon (Blue Topaz is a frequent substitute)

Zodiam gems

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

Capricorn • Dec 22-Jan 20 • Ruby
Aquarius • Jan 21-Feb 21 • Garnet
Pisces • Feb 22-Mar 21 • Amethyst
Aries • Mar 22-Apr 20 • Bloodstone
Taurus • Apr 21-May 21 • Sapphire
Gemini • May 22-June 21 • Agate
Cancer • June 22-July 22 • Emerald
Leo • July 23-Aug 22 • Onyx
Virgo • Aug 23-Sept 22 • Carnelian
Libra • Sept 23-Oct 23 • Peridot
Scorpio • Oct 24-Nov 21 • Beryl
Sagittarius • Nov 22-Dec 21 • Topaz

Anniversary stones

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.

Year
1
2
3
4
5
6
7
8
9
10

Gem
Gold Jewelry
Red Garnet
Pearls
Blue Topaz
Sapphire
Amethyst
Onyx
Tourmaline
Lapis Lazuli
Diamond

Year
11
12
13
14
15
16
17
18
19
20

Gem
Turquoise
Jade
Citrine
Opal
Ruby
Peridot
Watches
Cat's Eye
Aquamarine
Emerald

Year
25
30
35
40
45
50
55
60
65
70
75

Gem
Silver Jubilee
Pearl Jubilee
Emerald Jubilee
Ruby Jubilee
Sapphire Jubilee
Golden Jubilee
Alexandrite
Diamond Jubilee
Blue Spinel
Sapphire Jubilee
Diamond Jubilee

Year
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
25
30
35
40
45
50
55
60
65
70
75

Gem
Gold Jewelry
Red Garnet
Pearls
Blue Topaz
Sapphire
Amethyst
Onyx
Tourmaline
Lapis Lazuli
Diamond
Turquoise
Jade
Citrine
Opal
Ruby
Peridot
Watches
Cat's Eye
Aquamarine
Emerald
Silver Jubilee
Pearl Jubilee
Emerald Jubilee
Ruby Jubilee
Sapphire Jubilee
Golden Jubilee
Alexandrite
Diamond Jubilee
Blue Spinel
Sapphire Jubilee
Diamond Jubilee

Colored Gemstone Buying Guide

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. The one pictured here is a 5.25-ct. alexandrite shown in daylight (left) and incandescent light (right) — it comes from Tunduru, Tanzania. Learn More

(Photo: John McLean; Gem: Pala International)

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. The ones pictured here are a suite of demantoid garnets showing the typical range of colors possible. Learn More

(Photo: Wimon Manorotkul; Gems: Pala International)

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. The one pictured here is a Burmese jadeite. Learn More

(Photo: Wimon Manorotkul)

Lapis

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). The one pictured here is an Afghan lapis lazuli. Learn More

(Jewelry: The Collector; photo: John McLean)

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. The one pictured here is a padparadscha sapphire. Learn More

(Photo: Wimon Manorotkul; Gem: Pala International)

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. The ones pictured here are two different peridots, illustrating the importance of clarity. Learn More

(Photo: Robert Weldon)

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. The one pictured here is a 4.86-ct. star ruby. Learn More

(Photo: John McLean; Gem: Pala International)

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. The one pictured here is a 4-ct. plus Kashmir sapphire. Learn More

(Photo: John McLean; Gem: Pala International)

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). The one pictured here is a gorgeous Nigerian spessartite. Learn More

(Photo: Wimon Manorotkul)

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. The one pictured here is a spinel colored by cobalt. Learn More

(Photo: John McLean; Stone: Dr. Richard Bartholomeau)

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. The ones pictured here is a suite of tanzanite showing the typical range of colors possible. The ideal would be the center stone, which is not too light or dark. Learn More

(Photo: Wimon Manorotkul; Gems: Pala International)

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. The one pictured here is an imperial topaz from Brazil. Learn More

(Photo: Wimon Manorotkul)

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.” The one pictured here is an oval green tourmaline. Learn More

(Photo: Wimon Manorotkul)

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. The ones pictured here are a suite of tsavorites showing the typical range of colors possible with the ideal color in the middle. Learn More

(Photo: Wimon Manorotkul; Gem: Pala International)

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