Sapphire!
Sapphires have been treasured by people for centuries! Their beautiful color and hardness (9 on the Mohs scale) have made them a precious stone frequently used to adorn jewelry. Sapphire is the September birthstone and the gem of the 45th anniversary. A sapphire jubilee occurs after 65 years - Queen Elizabeth II marked her sapphire jubilee in 2017.
Most people don't realize that sapphire and ruby are both a type of mineral called Corundum and have the same chemical composition and mineral structure. Trace amounts of impurities determine the color of the stone, which can be blue, red, brilliant yellow, orange, green, and purple. The specific variation of corundum that is blue is a sapphire, red is a ruby, and all other colors are "fancy sapphires" and are referred to by their color, i.e. Yellow Sapphire, Orange Sapphire, etc. The blue in sapphires is caused by small amounts of titanium and iron.
Sapphires form in igneous (think magma or volcano) or metamorphic (think mountain building) environments but are often mined from river sediments where sapphires have washed into sands and gravels and are easier to find and collect (https://en.wikipedia.org/wiki/Sapphire, https://geology.com/gemstones/ruby-and-sapphire/).
For those who believe in the healing properties of stones, Sapphire is believed to support and encourage creative expression, intuition, luck, optimism, generosity, loyalty, self-appreciation, love, independence, balancing and centering. Sapphire is known as the "wisdom stone", each color of Sapphire brings its own particular wisdom. It is thought to release mental tension, depression, unwanted thoughts and spiritual confusion. Sapphire is believed to restore balance within the body, aligning the physical, mental and spiritual planes, bringing serenity and peace of mind. Sapphire is also known as a "stone of prosperity", attracting gifts of all kinds and fulfilling dreams and desires.(https://www.charmsoflight.com/sapphire-healing-properties).