Characteristics of Spinel:

Chemical Name: Magnesium aluminum oxide

Formula: MgAl2O4

Colors: Red, yellow, orange, red, blue, green, black, colorless

Structure: Cubic

Hardness: 8

Specific Gravity: 3.6

Refractive Index: 1.71-1.73

Lustre: Vitreous

Streak: White

Locations: Myanmar, Sri Lanka, Vietnam, Madagascar, Afghanistan, Tajikistan, Pakistan, Australia, Tanzania

What is Spinel? 

The name “spinel” comes from the Latin spinella, meaning “little thorn”, a reference to the sharp points of its crystals.

Gemstone spinel is a magnesium aluminum oxide, although the name is also given to a group of metal oxides, all of which have the same crystal structure. It is most familiar as a blue, purple, red or pink gem, but it can occur in other colors; its blood-red variety is sometimes called “ruby-spinel”. Another variety, star spinels, are so named as they display stars created by natural light reflection within the gem. Most spinel is recovered from stream gravels; the earliest gem dates from 100BCE and was discovered in a Buddhist tomb.

The Black Prince’s “Ruby” - A case of mistaken identity

The superb spinel known as the Black Prince’s Ruby was supposedly given to Edward, the Black Prince, the son of English King Edward III, by Peter the Cruel, king of Castille, after their joint victory at the Battle of Najera in 1367. Another English King, Henry V, wore it and nearly lost it at the Battle of Agincourt in 1415, and it was later set in the British Imperial State Crown. It was thought to be a ruby until the 19^th century.