Corundum vs. Sapphire — What's the Difference?
By Tayyaba Rehman & Fiza Rafique — Updated on May 9, 2024
Corundum is a mineral primarily composed of aluminum oxide, known for its hardness, while sapphire refers specifically to the blue variety of corundum.
Difference Between Corundum and Sapphire
Table of Contents
ADVERTISEMENT
Key Differences
Corundum is a naturally occurring mineral that ranks 9 on the Mohs scale of hardness, making it extremely durable. On the other hand, sapphire is a type of corundum that is prized for its vibrant blue color, which is caused by trace amounts of iron and titanium.
Corundum can be found in a variety of colors, including colorless, due to impurities or lack of impurities. Whereas sapphire, although commonly known for its blue hue, can also appear in pink, yellow, and green depending on the specific impurities.
The value of corundum as a raw mineral is typically lower compared to sapphires, which are considered gemstones and are highly valued in jewelry. On the other hand, sapphires, especially those that are vividly colored and clear, are among the most expensive gemstones in the world.
Corundum is used industrially for its abrasive qualities, particularly in sandpapers and cutting tools. Whereas sapphire is also used in industrial applications, such as in high-durability windows and electronic substrates, due to its exceptional hardness and transparency.
While corundum serves a significant role in geological studies to understand the conditions of mineral formation and regional metamorphism, sapphire is often studied in gemological contexts for its beauty and rarity.
ADVERTISEMENT
Comparison Chart
Composition
Aluminum oxide
Aluminum oxide with iron, titanium
Color Variety
Colorless, red, yellow, blue, more
Typically blue, also pink, yellow
Hardness
9 on Mohs scale
9 on Mohs scale
Primary Use
Abrasives, industrial
Jewelry, high-durability windows
Value
Lower for industrial use
High, considered precious
Compare with Definitions
Corundum
A naturally occurring substance with significant industrial applications.
Corundum is also used in watch crystals due to its scratch resistance.
Sapphire
A stone used in watches and high-stress environments.
Luxury watches often feature sapphire crystal glass for scratch resistance.
Corundum
The mineral base for rubies and sapphires, differing only in color.
The red variety of corundum is known as ruby.
Sapphire
A gemstone variety of corundum that is typically blue but can come in other colors.
The sapphire’s deep blue is due to its titanium and iron content.
Corundum
A crystalline form of aluminum oxide often used as an abrasive.
Synthetic corundum is widely used in making sandpaper.
Sapphire
A symbol of nobility, truth, and sincerity.
Sapphires have been prized as royal gems throughout history.
Corundum
A mineral used in scientific research to study crystallography.
Corundum's crystal structure helps scientists understand molecular bonds.
Sapphire
A material used in scientific instruments due to its optical properties.
Some scientific instruments use sapphire crystals for their transparency and hardness.
Corundum
A hard mineral consisting of aluminum oxide.
Corundum is second only to diamond in hardness.
Sapphire
A precious stone often used in high-end jewelry.
Sapphire engagement rings are popular for their durability and color.
Corundum
Corundum is a crystalline form of aluminium oxide (Al2O3) typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral.
Sapphire
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al2O3) with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors.
Corundum
An extremely hard mineral, aluminum oxide, Al2O3, sometimes containing iron, magnesia, or silica, that occurs in gem varieties such as ruby and sapphire and in a common black, brown, or blue form used chiefly in abrasives.
Sapphire
A transparent precious stone, typically blue, which is a variety of corundum (aluminium oxide)
A sapphire ring
Corundum
(mineral) An extremely hard mineral, a form of aluminum oxide with the chemical formula Al2O3, that occurs in the form of the gemstones sapphire and ruby; it is used as an abrasive.
Sapphire
A small hummingbird with shining blue or violet colours in its plumage and a short tail.
Corundum
The mineral alumina (Al2O3), as found native in a crystalline state. Transparent varieties are used as gemstones, including sapphire, which is the fine blue variety; the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond.
Sapphire
A clear hard variety of corundum used as a gemstone that is usually blue but may be any color except red.
Corundum
Very hard mineral used as an abrasive
Sapphire
A corundum gem.
Sapphire
The blue color of a gem sapphire.
Sapphire
Made of or resembling a gem sapphire.
Sapphire
Having the color of a blue sapphire.
Sapphire
Of or relating to a 65th anniversary.
Sapphire
(countable) A clear deep blue variety of corundum, valued as a precious stone.
Sapphire
A white, yellow, or purple variety of corundum, either clear or translucent.
Sapphire
A deep blue colour.
Sapphire
(countable) Any hummingbird in the genera Hylocharis and Chlorestes, as well as the rufous-throated sapphire, which is now in the genus Amazilia.
Sapphire
Any of the butterflies in the southern Asian lycaenid genus Heliophorus or the African lycaenid genus Iolaus.
Sapphire
Of a deep blue colour.
Sapphire
Pertaining to a 45th year
Sapphire
Native alumina or aluminium sesquioxide, Al2O3; corundum; esp., the blue transparent variety of corundum, highly prized as a gem.
Of rubies, sapphires, and of pearlés white.
Sapphire
The color of the gem; bright blue.
Sapphire
Of or resembling sapphire; sapphirine; blue.
Sapphire
A precious transparent stone of rich blue corundum valued as a gemstone
Sapphire
A transparent piece of sapphire that has been cut and polished and is valued as a precious gem
Sapphire
A light shade of blue
Sapphire
Having the color of a blue sapphire;
Sapphire eyes
Common Curiosities
How is corundum used industrially?
It is primarily used as an abrasive in various forms such as sandpaper and cutting tools.
Why are sapphires so valuable?
Sapphires are valued for their color, clarity, and durability, making them highly prized in jewelry.
What colors can sapphire come in?
While traditionally blue, sapphires can also be pink, yellow, green, and other colors depending on the impurities present.
Can corundum be transparent?
Yes, pure corundum can be transparent but is more commonly translucent or opaque due to impurities.
What is corundum?
Corundum is a hard, durable mineral composed of aluminum oxide, commonly used in industrial applications.
Can corundum be synthesized?
Yes, synthetic corundum is commonly produced for industrial and gemstone use.
What is the difference in hardness between corundum and sapphire?
There is no difference; both have a hardness of 9 on the Mohs scale.
Do all sapphires come from the same type of rock?
Sapphires can be found in various rock types but are typically sourced from igneous rocks or metamorphic rocks.
Where is corundum most commonly found?
Corundum deposits are found in Myanmar, India, Russia, Zimbabwe, and the United States.
What historical significance do sapphires hold?
Sapphires have been associated with royalty and romance and were believed to protect against envy and harm.
Is there a difference in the crystal structure between corundum and sapphire?
No, both share the same crystal structure; the differences lie in impurities and color.
Are all blue gemstones sapphires?
No, other blue gemstones include aquamarine, topaz, and lapis lazuli.
How does the price of corundum compare to sapphire?
Corundum is generally less expensive unless it qualifies as a gemstone-quality sapphire.
What makes sapphires blue?
The presence of iron and titanium impurities gives sapphires their characteristic blue color.
What are the main uses of sapphire aside from jewelry?
Sapphire is used in industrial applications such as in optical components and high-durability windows.
Share Your Discovery
Previous Comparison
Concourse vs. Corridor
Next Comparison
Warrior vs. WorrierAuthor Spotlight
Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
