The gemstone group corundum
The corundum group of gemstones includes some of the most precious gemstones. This mineral comes in a wide range of colors. All red varieties are called rubies , and other colors are called sapphires , with blue being the most popular. With a Mohs hardness of 9, corundum is one of the hardest minerals - just one level below the invincible diamond.
If a corundum does not contain any deposits of foreign minerals, it is colorless and is called leucosapphire.
A special feature are the pink-orange Padparadscha sapphires, whose name is derived from the Sinhalese word for lotus flower.
Edelberylle – the beryl and its variety of colors
If a beryl has a golden yellow or lemon yellow color, it is called golden beryl . In contrast to emeralds, where inclusions are the norm, these gemstones are characterized by their almost complete absence of impurities.
If the yellow is very light and also has a slight green tone, it is a heliodor (Greek: gift of the sun).
The colorless beryl was named goshenite after its location in Goshen, Massachusetts.
A morganite is a pink beryl, with the color palette ranging from a cool light violet to salmon and warm peach. It was named in honor of the banker and passionate collector of gemstones and art objects, John Pierpont Morgan (1816-1884).
There is also the rare gooseberry red to violet beryl. Previously known as bixbite, it is now mainly referred to as red beryl .
Common treatments of corundum gemstones
It is common practice to improve the color of corundums by heat treatment. This does not affect the quality of the gemstones, but untreated rubies and sapphires command higher prices.
