Jacqueline Kennedy Onassis was, without question, one of the great icons of the twentieth century. Wed to both an American president and a Greek shipping magnate, she was also a mother, a book editor, and a patron of the arts who spearheaded the fight to save New York City’s Grand Central Station. A notoriously private [...]

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Color: oxide Mohs’ hardness: 9 Transparency: Opaque, translucent, transparent Luster: Vitreous to adamantine Fracture: Small, conchoidal, uneven, splintery, brittle Crystal system: Hexagonal (trigonal); hexagonal prisms or tablets, rhombohedrons Cleavage: None Specific gravity: 3.97-4.05 Refractive index: 1.766-1.774 Dispersion: 0.018 Pleochroism: Strong; yellow-red, deep ruby-red Fluorescence: Strong; ruby-red Occurrence: Worldwide Astrology: July birthstone, also connected with Cancer, [...]

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Color: Colorless, yellow, pale sheen; rainbow moonstone has blue sheen Chemical composition: K(AlSi3O8) potassium aluminum silicate Mohs’ hardness: 6-6 ½ Transparency: Turbid, transparent Luster: Vitreous Fracture: Uneven, conchoidal Crystal system: Monoclinic; prismatic Cleavage: Perfect Specific gravity: 2.56-2.62 Refractive index: 1.522-1.530 Dispersion: 0.012 Pleochroism: None Fluorescence: Weak; bluish, orange Occurrence: Australia, Brazil, India, Malagasy Republic, Mexico, [...]

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Color: Sapphire-blue, amethyst, violet Chemical composition: Ca2Al3 (O/OH/SiO4/SiO2) calcium aluminium silicate Mohs’ hardness: 6 ½-7 Transparency: Transparent Luster: Vitreous Fracture: Uneven, brittle Crystal system: Orthorhombic, multi-faceted prisms, mostly striated Cleavage: Perfect Specific gravity: 3.35 Refractive index: 1.691-1.700 Dispersion: 0.030 Pleochroism: Very strong; violet, blue, brown Fluorescence: None Occurrence: East Africa (Tanzania) Astrology: recently designated a [...]

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Color: Colorless, red, orange, yellow, green, blue, violet, nearly black Chemical composition: CaF2 calcium fluoride Mohs’ hardness: 4 Transparency: Transparent, translucent Luster: Vitreous Fracture: Even to conchoidal, brittle Crystal system: Isometric; cubes, octahedra Cleavage: Perfect Specific gravity: 3.18 Refractive index: 1.434 Dispersion: 0.007 Pleochroism: None Fluorescence: Usually strong; blue-violet Occurrence: Canada, China, England, France, Germany, [...]

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Fossil coral was once the skeleton of a coral polyps whose organic structure has been transformed to stone. After the coral died, the skeleton became saturated with water that contained dissolved silica, the same mineral that is the principal component of quartz, chalcedony, agate, and jasper. In this case, the silica replaced the coral’s soft [...]

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Color: Light blue, blue, blue-green Chemical composition: Al2Be3(Si8O18) aluminium beryllium sliciate Mohs’ hardness: 7 ½-8 Transparency: Transparent to opaque Luster: Vitreous Fracture: Conchoidal, uneven, brittle Crystal system: Hexagonal (trigonal); long prisms Cleavage: Imperfect Specific gravity: 2.67-2.71 Refractive index: 1.577-1.583 Dispersion: 0.014 Pleochroism: Definite, nearly colorless-light blue Fluorescence: None Occurrence: Afghanistan, Australia, Brazil, India, Kenya Malagasy [...]

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Color: Pale lavender to deep purple Chemical composition: SiO2 silicon dioxide Moh’s Hardness: 7 Transparency: Transparent Luster: Vitreous Fracture: Conchoidal, very brittle Crystal system: Hexagonal (trigonal) with hexagonal prisms Specific gravity: 2.63-2.65 Streak: White Refractive index: 1.544-1.553 Dispersion: 0.013 Pleochroism: Very weak; violet, gray-violet Fluorescence: Weak; greenish Occurrence: Africa, Brazil, Britain, Canada, India, Malagasy Republic, [...]

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Color: Colorless, pink, red, yellow, brown, green, blue, violet, black, multi-colored Chemical composition: (NaLiCa) (Fe11Mg Mn Al)3 Al8 (OH)4 (BO3)Si6O18) aluminum borate silicate, complicated and changeable composition Mohs’ hardness: 7-7 ½ Transparency: Transparent, opaque Luster: Vitreous Fracture: Uneven, small conchoidal, brittle Crystal system: Hexagonal (trigonal) Cleavage: None Specific gravity: 3.02-3.26 (varies with the color) Streak: [...]

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Garnets were said to be magnets for prosperity and glory, and to dream of them was said to symbolize the gaining of wealth. Garnets were also came to be an emblem of truth and fidelity. Perhaps as a symbol of faith even beyond death, Italian widows favored garnets and the stone became known as pietra della [...]

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