[A7] What is the difference between ruby and sapphire? Explaining why the colors are different even though they are the same mineral
What is the difference between ruby and sapphire? Explaining why the colors are different even though they are the same mineral
SUPERVISOR / Supervision
Takazo Saito
Selby EC/SNS/Ruth/Production Department Manager
Differences between ruby and sapphire [Conclusion list]
In conclusion,Ruby and sapphire are "the same corundum mineral"The only difference is the trace elements that determine the color. Red corundum is defined as ruby, and other colors (blue, yellow, green, pink, etc.) are defined as sapphire.
⚖ KEY COMPARISON
the two stonesa “brother” relationship. Although they belong to the same mineral group, they have different characteristics depending on the trace elements they contain.
RUBY
ruby
Red gem / corundum (red)
coloring element
Chromium (Cr)
color
red only
hardness
Morse 9
stone words
passion, love, victory
birthstone
July
SAPPHIRE
sapphire
Blue ball / corundum (other than red)
coloring element
Iron (Fe) + Titanium (Ti)
color
Blue, yellow, green, pink, etc.
hardness
Morse 9
stone words
Honesty, Loyalty, Intelligence
birthstone
september
In fact, the same mineral “corundum”
The best facts about rubies and sapphires are:"Both are minerals called corundum."That is. The two gemstones, which many people think are different, are actually chemically the exact same substance.
What is corundum?
Corundum isAluminum oxide with the chemical formula Al₂O₃minerals. Among the naturally occurring minerals on earth, it is the second hardest after diamond.Mohs hardness 9We are proud of It is an extremely hard and stable mineral that has been used industrially as sandpaper and abrasives.
Common features of crystal structures
Ruby and sapphire,Hexagonal (trigonal) crystal structureIt forms hexagonal columnar or barrel-shaped crystals. All physical properties such as refractive index, specific gravity, Mohs hardness, and cleavage are the same.The only difference is the trace elements that produce color.That's it.
FIG.01 / FAMILY TREE
Ruby and sapphire branch from corundum (Al₂O₃)
Figure 1: The same corundum mineral produces two gemstones with different trace elements.
Elements that cause different colors
Although they are both corundum, rubies are red and sapphires are blue or yellow.Differences in trace elements (impurities) mixed into the crystal latticeThis is due to
Ruby: Chromium produces red color.
What makes ruby red?Chromium (Cr³⁺). The chromium ions incorporated into corundum's crystal lattice absorb blue to green wavelengths of visible light, and strongly reflect and transmit red wavelengths. The higher the chromium concentration, the brighter the red color, and the highest grade, Pigeon Blood, contains the optimum concentration of chromium in the crystals. At the same time, chromium is exposed to ultraviolet light.strong red fluorescenceIt emits a "fiery glow from within" that is unique to rubies from Myanmar.
Sapphire: Iron and titanium produce blue color.
What is responsible for the color development of blue sapphire?Combination of iron (Fe²⁺) and titanium (Ti⁴⁺). Electrons move between both elements when they are adjacent in the crystal lattice"Intermetallic charge transfer (IVCT)"occurs, absorbing yellow to red wavelengths and transmitting blue light. When only iron is used, it is yellow to green, and when only titanium is used, it is almost colorless."Exquisite combination of iron and titanium"This is the source of sapphire blue.
FIG.02 / COLOR ORIGIN
Differences in coloring mechanism (light absorption and transmission)
Figure 2: In ruby, Cr absorbs blue to green and transmits red. Sapphire transmits blue light due to charge transfer between Fe and Ti.
Difference in value and price
In terms of market value,Ruby tends to be more expensive if it is of the same quality.There is. This is because rubies are produced in smaller quantities, and large, high-quality rubies are extremely rare. Sapphire comes in a wide variety of colors and is distributed in relatively large quantities, giving a wide range of choices.royal blue kashmiretc. are traded at high prices comparable to rubies.
| Item | Ruby (1ct high quality) | Sapphire (1ct high quality) |
|---|---|---|
| standard quality | 200,000 to 600,000 yen | 100,000 to 300,000 yen |
| high quality | 600,000 to 2 million yen | 300,000 to 1 million yen |
| highest peak | 2 million to tens of millions of yen (Pigeon Blood) |
1 million to tens of millions of yen (royal blue) |
| Non-heated premium | 2 to 10 times more than heated products | 2 to 5 times more than heated products |
Difference between history and legend
Although they are the same corundum, ruby and sapphire areContrasting roles in historical and cultural meaningsI have been in charge of this.
| Item | ruby | sapphire |
|---|---|---|
| ancient title | Queen of Jewels / King of Jewels (ratnaraj) | Philosopher's Stone/Stone of Truth |
| symbol | Passion, love, victory, blood | Sincerity, Wisdom, Sky, Divinity |
| favorite royal family | King of Burma/Emperor of India | Clergy/British Royal Family |
| famous stones | Sunrise Ruby (25.59ct) | Star of India (563ct) |
| Biblical account | symbol of strength | color of god's throne |
The border between pink sapphire and ruby
What is always debated in the industry is"Where does the ruby end and where does the pink sapphire begin?"The problem. Both are the same corundum + chrome, the only difference being the shade of color.
Distinction based on GIA standards
According to the current standards of GIA (Gemological Institute of America),Items with saturation and brightness at a level that can be recognized as “red” = ruby; less than that = pink sapphireis defined as SpecificallySaturation of “strong red” (more than strong red)is considered the borderline for ruby, and colors paler than this are classified as pink sapphires.
Differences in definition depending on country
There are no strict internationally unified standards;Interpretation of boundaries differs depending on country/region. Traditional markets in Asia such as Thailand and Myanmar tend to call rubies even if they are slightly pink, and identification organizations in the United States and Switzerland tend to be relatively strict and only certify only strong reds as rubies. This fluctuation in standards is why the same stone is sometimes called "ruby" or "pink sapphire" depending on the country.
FIG.03 / BOUNDARY
Pink sapphire⇔ruby color boundary gradation
Figure 3: The boundaries are fuzzy. The classification changes depending on the classification organization due to slight differences.
Difference in production area
Ruby and sapphire are produced in different regions, with some overlapping and different.
| Production area | ruby | sapphire |
|---|---|---|
| Myanmar (Mogok) | The highest peak (Pigeon Blood) | royal blue production |
| Sri Lanka (Ceylon) | Small amount/pinkish | Main production areas (cornflower blue) |
| mozambique | Modern main distribution | small quantity production |
| Kashmir (India) | rare | Highest peak (Kashmir blue) |
| Thailand/Cambodia | Dark red/Decreased distribution | black star etc. |
| madagascar | small amount | One of the main production areas in recent years |
Differences in usage and popularity
There are also differences in how they are used as jewelry and the occasions in which they are preferred.
| Item | ruby | sapphire |
|---|---|---|
| engagement ring | Rising in popularity as a symbol of passionate love | British royal tradition (Princess Diana → Duchess Catherine) |
| commemorative jewelry | 40th wedding anniversary "Ruby wedding" | 45th wedding anniversary "Sapphire wedding" |
| birthstone | Born in July | Born in September |
| For men | cabochon ring tie pin | Cufflinks/tie pins standard |
| power stone | Luck in battle/Luck in love | Improve work luck and intelligence |
Frequently asked questions (FAQ)
Are rubies and sapphires really the same mineral?
Yes, both are the same mineral called "Corundum (Al₂O₃)". The only difference is the trace elements incorporated into the crystal lattice. Rubies are called rubies when they contain chromium and turn red, and sapphires when they have other colors.
What is the difference between pink sapphire and ruby?
Both are colored by corundum and chromium, and are chemically the same. They are classified according to their color depth (chromium concentration). According to GIA standards, a ruby with a saturation of ``strong red'' or higher is considered a ruby, and anything paler than that is considered a pink sapphire.
Which is more valuable: ruby or sapphire?
Ruby tends to be more expensive if it is of the same quality. However, there are some sapphires from Kashmir, such as padparadscha sapphire (lotus flower color), that are sold at ruby-grade sapphire prices, so it is difficult to generalize.
Do you have green corundum?
Yes, it exists as "green sapphire". It contains a lot of iron and has a green color due to the combination of cobalt and titanium. This is a relatively rare variation.
Is there a difference in hardness or durability?
No, there isn't. Both have a Mohs hardness of 9 because they are made of the same corundum mineral. It is second in hardness to diamond, making it the perfect choice for everyday jewelry.
Which one is suitable for an engagement ring?
Both are suitable. Ruby means "passion and eternal love," and sapphire means "honesty and fidelity," and both have meanings that symbolize marriage. Choose according to your tastes and thoughts.
Summary
Key points of this article
- Ruby and sapphire are the same corundum (Al₂O₃) mineral.
- Red corundum = ruby, other colors = sapphire
- Ruby is colored by chromium, and blue sapphire is colored by iron and titanium.
- Both have a Mohs hardness of 9. Same durability
- The border between pink sapphire and ruby is a difference in saturation, and there are standards depending on the country.
- Ruby is a little more valuable if it is of the same quality. Both are popular for collections and engagement rings.
Ruby and sapphire are like ``brothers'' and are gemstones with different brilliance born from the same earth.Do you choose red passion or blue intelligence?--It depends on the owner's thoughts and story. At Selby, we import both types of gemstones directly from the source and deliver them with reliable identification. Please choose the stone that is suitable for you.
SUPERVISED BY
Takazo Saito
Selby EC/SNS/Ruth/Production Department Manager. A gemstone specialist who is familiar with the identification and purchasing of corundum minerals in general.