Sapphire

**Sapphire** is a type of the mineral corundum, an aluminium oxide (Al<sub>2</sub>O<sub>3</sub>).   Sapphires are a type of corundum, the same mineral as rubies. Because they have different impurities, they are blue and not red.

Sapphire can be found in the ground or it can be made in large crystal. Blue sapphires are the most famous kind, but they can be many different colors, like amber and orange.

Sapphires have a long history. Tradition says that the tablets of the Ten Commandments were made of sapphire, so strong a hammer could not break them, and would break instead if it hit them. The ancient Persians believed that the earth sat on a big sapphire and that the big sapphire made the sky blue.

A lot of ancient people thought rubies made people calm down, as well as cure their bruises.

Sapphires have been used by kings and queens for a long time as a symbol of luck, virtue, wisdom, and holiness.  Princess Diana and Princess Anne both received sapphire engagement rings and the British Crown Jewels are full of large blue sapphires, the symbol of kind and wise rulers.

Sapphires represent September. It symbolizes telling the truth and doing what you said you would.

Sapphire is actually just corundum and is one of the hardest minerals on the hardness scale.  Since sapphire is the second hardest mineral in the hardness scale, it is sometimes used as a polishing tool.

This mineral is found in gem gravel deposits. These deposits are formed from the heat of metamorphic or igneous rock plateaus. The places where sapphire is formed abundantly are Myanmar, Thailand, India and Sri Lanka. The most costly and beautiful sapphires are shipped from Kashmir, India.  In other words, sapphire is mostly found in Asia. Recent findings of sapphire have taken place in Australia, Kenya, and Tanzania.

Sapphire was the first mineral to be lab grown in a strategy called "flame fusion". Another strategy, slightly harder to use, "flux growth" was used to lab grow sapphire.

Heating yellow, light yellow, or colorless sapphire from 1500-1900oc can turn into a dark yellow, gold, golden brown, orange, or a reddish brown colored sapphire. There is a specific kind of sapphire called Star sapphires have whitish pieces of rutile or silk as some call it. Star sapphires can be heated to remove the blue color of sapphire and can be heated even more to get the blue color back and remove the white silk.

## Natural Sapphires

Sapphire is a precious gemstone that comes from the mineral corundum. When corundum is red, it’s called ruby; when it’s any other color, it’s called sapphire. While blue sapphires are the most famous, sapphires can also be gray, black, colorless, or even pinkish orange the special pinkish orange ones are called padparadscha.

Sapphires are found in many parts of the world. Big deposits exist in countries like Australia, Afghanistan, Cambodia, China, Colombia, Ethiopia, India (especially Jammu and Kashmir), Kenya, Laos, Madagascar, Malawi, Mozambique, Myanmar (Burma), Nigeria, Rwanda, Sri Lanka, Tanzania, Thailand, the United States (Montana), and Vietnam. Sometimes sapphires and rubies come from the same area, but they usually form in different types of rocks. For example, in Myanmar’s famous Mogok area, rubies form in marble while sapphires come from rocks called granitic pegmatites or corundum syenites.

Not every sapphire from a famous place is of high quality. The place where a sapphire is found does not always mean it’s better. Still, sapphires from Jammu and Kashmir are often the most prized. Sapphires from Burma, Sri Lanka, and Madagascar can also be very beautiful and valuable.

The price of a natural sapphire depends on many things: its color, clarity, size, how well it’s cut, and overall quality. Untreated sapphires, which have not been heated or altered, are worth much more than treated ones. Where the sapphire comes from can also affect its price. For larger sapphires (one carat or more), buyers usually ask for a report from a trusted gem lab like GIA, Lotus Gemology, or SSEF before buying.

## References

U of Texas. "corundum." ruby and sapphire notes. U of Texas, 24 Aug. 2012. Web.
30 Oct. 2012. <http://www.geo.utexas.edu/courses/347k/redesign/gem_notes/
corundum/corundum_triple_frame.htm>.

Gait, Robert I. "Sapphire." World Book Advanced. World Book, 2012.Web. 4 Dec. 2012.

## Infobox (mineral)

- **name**: Sapphire
- **category**: Oxide mineral
- **image**: Logan Sapphire, National Museum of Natural History, Washington DC.jpg
- **caption**: The 422.99-Carat (mass), carat Logan sapphire
- **formula**: aluminium oxide, aluminium, Al<sub>2</sub>oxygen, O<sub>3</sub>
- **color**: Every color except for red – which is called a ruby – or pinkish-orange (the padparadscha)
- **habit**: massive and granular
- **system**: Trigonal
Symbol (2/m)
Space Group: Rc
- **cleavage**: none
- **fracture**: conchoidal, splintery
- **mohs**: 9.0
- **luster**: vitreous
- **refractive**: n<sub>ω</sub>=1.768–1.772
n<sub>ε</sub>=1.760–1.763,
Birefringence 0.008
- **opticalprop**: Abbe number 72.2
- **pleochroism**: Strong
- **streak**: white
- **gravity**: 3.95–4.03
- **melt**: 2030–2050 °C
- **fusibility**: infusible
- **solubility**: Insoluble
- **other**: coefficient of thermal expansion (5.0–6.6)×10<sup>−6</sup>/K