What is the Difference Between Amethyst and Blue Sapphire

The main difference between amethyst and blue sapphire is their hardness: blue sapphire has a hardness of 9 on the Mohs scale, while amethyst has a hardness of 7 on the Mohs scale.  

Amethysts and blue sapphires are two colorful gemstones that are popular all over the world. The color of amethysts ranges from deep reddish-purple to pale lilac, whereas sapphires mainly occur in blue color. Amethyst is the birthstone for February, while blue sapphire is the birthstone for September.

Key Areas Covered

1. What is Amethyst 
     – Definition, Features 
2. What is Blue Sapphire
    – Definition, Features 
3. Difference Between Amethyst and Blue Sapphire
     – Comparison of Key Differences

Key Terms

Amethyst, Blue Sapphire, Gemstones

Difference Between Amethyst and Blue Sapphire - Comparison Summary

What is Amethyst

Amethyst is a popular gemstone due to its attractive purple color. It’s a crystalline quartz with colors ranging from deep reddish-purple to pale lilac. The value of an amethyst gemstone depends almost entirely on its color. Reddish purple amethysts are the most popular forms of amethysts. Furthermore, amethysts are widely available, durable, and affordable. They are also readily available in large sizes. Therefore, amethysts are a favorite gemstone of jewelers, artisans, and craftsmen. In fact, amethyst is the traditional birthstone for February.

Amethyst vs Blue Sapphire

When considering their properties, amethysts have a relatively high hardness of 7 and a specific gravity of 2.6 to 2.7. The physical properties of amethyst are nearly identical to those of other quartz; their main difference is in color. High-quality amethysts are found in Siberia, Brazil, Sri Lanka, and the Far East.

What is Blue Sapphire

Sapphires are a variety of the mineral corundum, composed of aluminum oxide with trace amounts of elements like titanium, iron, chromium, magnesium, or vanadium. Sapphires are one of the four precious gemstones. They are usually blue in color, hence the name ‘blue sapphire.’ They also occur in purple, orange, yellow, and green colors. There are also parti-sapphires, which show two or more colors. 

Sapphires are commonly cut and polished and worn in jewelry. Sapphires are the third hardest mineral (after diamond and moissanite) and have a hardness of 9 on the Mohs scale. Because of this hardness, we also use it in non-ornamental applications like high-durability windows, infrared optical components, and wristwatch crystals. Their specific gravity is 3.98–4.06. Furthermore, blue sapphire is vitreous and has a colorless streak. They are transparent to nearly opaque. They also have poor cleavage.

Compare Amethyst and Blue Sapphire - What's the difference?

Sapphires form as a result of several processes on the earth’s surface, including high pressure and temperature. When liquid magma deep within the earth cools, it makes minerals crystalize. Sapphires are the finest and purest forms of corundum and take millions of years to form. They are found globally. The main sources of sapphires are India, Colombia, Cambodia, and Kenya.

Difference Between Amethyst and Blue Sapphire

Definition

Amethyst is a crystalline quartz with colors ranging from deep reddish-purple to pale lilac, while blue sapphire is a blue-colored transparent precious stone, which is a variety of corundum (aluminum oxide).

Nature

Amethyst is a semi-precious stone, while blue sapphire is a precious stone.

Hardness

Blue sapphire has a higher hardness than amethyst. Blue sapphire has a hardness of 9 on the Mohs scale, while amethyst has a hardness of 7 on the Mohs scale.

Chemical Composition

Blue sapphire is made of aluminum oxide, whereas amethyst is made of quartz, which has vanadium and silicon oxide.

Refractive Index 

Amethyst has a refractive index of 1.544 to 1.533, while blue sapphire has a refractive index of 1.762 to 1.768.

Rarity

Blue sapphires tend to be rarer and more valuable than amethysts.

Birthstone

Amethyst is the birthstone for February, whereas blue sapphire is the birthstone for September.

Conclusion

The main difference between amethyst and blue sapphire is their hardness: blue sapphire has a hardness of 9 on the Mohs scale, while amethyst has a hardness of 7 on the Mohs scale. 

Reference:

1. “What is a Sapphire? – Gemstone Facts And Information.” Leibish.
2. “Amethyst.” Geology.com

Image Courtesy:

1. “Amethyst. Magaliesburg, South Africa” By JJ Harrison – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Logan Sapphire SI” By Chip Clark, Smithsonian staff – Museum of Natural History, Smithsonian Institution, Image Number: 95-40288 Catalog Number: G3703 and Gem Gallery (Public Domain) via Commons Wikimedia

About the Author: Hasa

Hasanthi is a seasoned content writer and editor with over 8 years of experience. Armed with a BA degree in English and a knack for digital marketing, she explores her passions for literature, history, culture, and food through her engaging and informative writing.

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