Corundum has two primary gem varieties: ruby and sapphire. Rubies are red due to the presence of chromium, and sapphires exhibit a range of colors depending on what transition metal is …

Rubies are specifically the red variety of corundum. Ruby variety corundum is colored only by chromium, which is a rare element. Corundum can come in many other colors too, like velvety …

Ruby is red corundum. All other colors of corundum are called sapphires. The corundum family of gemstones consists of ruby and sapphire. Corundum is very compact, dense, and lacks …

Corundum as ruby, sapphire, and fancy sapphire: Gem-quality corundum is a highly prized and valuable material. When it is bright red in color it is called "ruby." When it is blue it is called …

Corundum is best known for its gem varieties, Ruby and Sapphire. Ruby and Sapphire are scientifically the same mineral, but just differ in color. Ruby is the red variety, and Sapphire is …

Rubies: The most desired variety of corundum is the ruby. The red color is produced by trace amounts of chromium in the mineral. These two beautiful rubies were mined in Madagascar. …

2020年1月31日 · Ruby and sapphire are gem varieties of the mineral corundum. The chromophores are chromium (Cr 3+ ) in ruby, and iron and titanium (Fe 2+ and Ti 4+ ) in blue …

2024年7月1日 · Ruby is a red variety of the mineral corundum, and is one of the most valuable and sought-after gemstones in the world. It has a hardness of 9 on the Mohs scale, making it …

Ruby and sapphire (usually blue, but also in every other color) have been the most important colored gemstones for several thousand years. Originating historically in southeast and central …

2021年4月28日 · This lecture text presents features of the fascinating mineral corundum and its gem varieties, ruby and sapphire. The geologic occurrences of its varieties and the best …