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Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al2O3) with trace amounts of elements such as iron, titanium, cobalt, lead, chromium, vanadium, magnesium, boron, and silicon. The name sapphire is derived from the Latin word sapphirus, itself from the Greek word sappheiros (σάπφειρος), which referred to lapis lazuli. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on the locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large crystal boules. Because of the remarkable hardness of sapphires – 9 on the Mohs scale (the third-hardest mineral, after diamond at 10 and moissanite at 9.5) – sapphires are also used in some non-ornamental applications, such as infrared optical components, high-durability windows, wristwatch crystals and movement bearings, and very thin electronic wafers, which are used as the insulating substrates of special-purpose solid-state electronics such as integrated circuits and GaN-based blue LEDs. Sapphire is the birthstone for September and the gem of the 45th anniversary. A sapphire jubilee occurs after 65 years.
Ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum. Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapphires. Ruby is one of the traditional cardinal gems, alongside amethyst, sapphire, emerald, and diamond. The word ruby comes from ruber, Latin for red. The color of a ruby is due to the element chromium.
The Cullinan Diamond is the largest gem-quality rough diamond ever found, weighing 3,106 carats (621.20 g), discovered at the Premier No.2 mine in Cullinan, South Africa, on 26 January 1905. It was named after Thomas Cullinan, the owner of the mine. In April 1905, it was put on sale in London, but despite considerable interest, it was still unsold after two years. In 1907, the Transvaal Colony government bought the Cullinan and Prime Minister Louis Botha presented it to Edward VII, the British king who reigned over the territory. It was then cut by Joseph Asscher & Co. in Amsterdam.
The Imperial State Crown is a state crown of the Crown Jewels of the United Kingdom. It has existed in various forms since the 15th century and the present version was created in 1937. The crown is adorned with 3,170 precious stones, including the Cullinan II diamond, St Edward's Sapphire, the Stuart Sapphire, and the Black Prince's Ruby.
The Star of India is a 563.35-carat star sapphire, one of the largest such gems in the world. It is almost flawless and is unusual in that it has stars on both sides of the stone. The greyish-blue gem was mined in Sri Lanka and is housed in the American Museum of Natural History in New York City.
The Logan Sapphire is a 422.98-carat (84.596 g) sapphire from Sri Lanka. One of the largest blue faceted sapphires in the world, it was owned by Sir Victor Sassoon and then purchased by M. Robert Guggenheim as a gift for his wife, Rebecca Pollard Guggenheim, who donated the sapphire to the Smithsonian Institution in 1960. The sapphire's name is derived from Rebecca's new surname after marrying John A. Logan. It has been displayed in the National Gem Collection of the National Museum of Natural History in Washington, D.C., since 1971. It is a mixed cushion-cut sapphire, approximately the size of a large chicken egg, and set in a silver and gold brooch surrounded by 20 round brilliant-cut diamonds.
Harry Winston was an American jeweler. He donated the Hope Diamond to the Smithsonian Institution in 1958 after owning it for a decade. He also traded the Portuguese Diamond to the Smithsonian in 1963 in exchange for 3,800 carats of small diamonds.
The Star of Bombay is a 182-carat (36.4-g) cabochon-cut star sapphire originating in Sri Lanka. The violet-blue gem was given to silent film actress Mary Pickford by her husband, Douglas Fairbanks. She bequeathed it to the Smithsonian Institution. It is the namesake of the popular alcoholic beverage Bombay Sapphire, a British-manufactured gin.
The Stuart Sapphire is a blue sapphire that forms part of the British Crown Jewels. It weighs 104 carats and is believed to have originated from Asia, potentially present-day Afghanistan, Sri Lanka, Myanmar or Kashmir.
The Star of Asia is a large, 330 carats (66 g) cabochon-cut star sapphire now in the Smithsonian National Museum of Natural History. It is noted for its significant size and is considered to be one of the largest of its type. Adding to its aesthetic value are its rich blue colour and clear star, formed from three intersecting rutile striations.
Yogo sapphires are blue sapphires, a colored variety of corundum, found in Montana, primarily in Yogo Gulch in Judith Basin County, Montana. Yogo sapphires are typically cornflower blue, a result of trace amounts of iron and titanium. They have high uniform clarity and maintain their brilliance under artificial light. Because Yogo sapphires occur within a vertically dipping resistive igneous dike, mining efforts have been sporadic and rarely profitable. It is estimated that at least 28 million carats of Yogo sapphires are still in the ground. Jewelry containing Yogo sapphires was given to First Ladies Florence Harding and Bess Truman; in addition, many gems were sold in Europe, though promoters' claims that Yogo sapphires are in the crown jewels of England or the engagement ring of Princess Diana are dubious. Today, several Yogo sapphires are part of the Smithsonian Institution's gem collection.
The Star of Adam is an oval-shaped blue star sapphire, currently the largest star sapphire in the world. It weighs 1,404.49 carats. Prior to its discovery in 2015, the Black Star of Queensland, weighing 733 carats (146.6 g), was the largest star sapphire gem in the world.
The Sapphire Jubilee of Elizabeth II on 6 February 2017, marked 65 years of Queen Elizabeth II's reign. The longest-reigning monarch in British history, Elizabeth II was the first British monarch to have a sapphire jubilee.
The Allison and Roberto Mignone Halls of Gems and Minerals are a series of exhibition halls at the American Museum of Natural History on the Upper West Side in Manhattan, New York City. The halls opened on June 12, 2021, as a complete redesign of their predecessors, the Harry Frank Guggenheim Hall of Gems and Minerals and Morgan Memorial Hall of Gems. The halls feature thousands of rare gems, mineral specimens and pieces of jewelry.
Serendipity Sapphire is the world's largest star sapphire cluster, and it weighs 510 kilograms. It was found in Kahawatte, in the Ratnapura District, Sri Lanka, in July 2021. Its worth is estimated to be up to US$100 million.
The Millennium Sapphire is a blue sapphire discovered in 1995 in Madagascar, the natural dark–blue gem weighed 89,850 carats.
The Queen Marie of Romania Sapphire is a 478.68 carat Cornflower blue cushion cut Ceylon sapphire. When it was sold at Christie's in 2003, it was the largest sapphire ever offered at auction. It is named for its association with its first owner, Marie of Edinburgh, Queen of Romania.