Aluminum, crystals of aluminum oxide.
Aluminum
Rubies and sapphires are both made from corundum but both have different minerals that colour them. Rubies are always red and sapphires are any colour but red
See the related links for a website that has a lot of stuff about star sapphires and rubies!
Rubies and sapphires are both varieties of the mineral corundum, which is composed of aluminum oxide. The presence of trace elements gives rubies their red color, while sapphires can be found in various colors, including blue, due to different impurities. Rubies are often used in fine jewelry, while sapphires are prized for their beauty and durability. Interestingly, both rubies and sapphires can be used to make industrial-grade sandpaper, as their hardness allows for effective abrasion.
It is true that rubies, sapphires, and emeralds are more rare than diamonds. The reason is that the elements which make up rubies, sapphires, and emeralds which give them their color are more rare in the environment than carbon which is what diamonds are made of.
No, sapphires are typically blue in color. Red sapphires are actually a specific type of corundum called rubies. Rubies are red due to the presence of trace elements like chromium in their crystal structure.
Sapphires are the gemstone version of the mineral corundum. Sapphires come in every color except red corundum which are considered rubies.
Sapphires come in many colors, the red ones are called rubies, so they're basically the same thing but different colors. did you know that sapphires are the same as rubies except that they are different colors and did you know that there is a type of ruby called star ruby and a sapphire called star sapphire.
Aluminium Oxide i.e Al2O3
Rubies can and so can sapphires and diamonds
Rubies and sapphires are both gem-quality variants of the same mineral: corundum. The only difference is in color. Red or pink corundum is ruby. Corundum in other colors is sapphire.
extreme hardness