Why are rubies red and emeralds green? Their colors come from the same metal in their atomic structure

The colors of rubies and emeralds are so striking that they define shades of red and green – ruby red and emerald green. But ...
Nature

Manufacture of Alkali-free Corundum of Tabular Crystal Form

THERE are several modifications of aluminium oxide, the most important of which are α- and γ-forms. The latter cannot be considered as aluminium oxide proper, since it contains substantial quantities ...
Global Times

Giant natural blue sapphire on display in Sri Lanka

Photo taken on Dec. 15, 2021 shows the natural corundum crystal blue sapphire named "Queen of Asia" on display in Horana, Sri Lanka. Sri Lankan authorities on Monday said the country had unearthed the ...
Asheville Citizen-Times

Visiting Our Past: The great sapphire search got gritty

“At the Corundum Hill Mine (near Highlands), various shades of ruby gem corundum have been found,” the U.S. Geological Survey reported in 1906. However, though the gems were similar to the red rubies ...
The Conversation

Why are rubies red and emeralds green? Their colors come from the same metal in their atomic structure

Daniel Freedman does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...