The name opal derives from the Greek Opallos, meaning "to see a change (of color)." Opals range in color from milky white to black with flashes of yellow, orange, green, red, and blue. An opal's beauty is the product of contrast between its color play and its background. Opal is a formation of non-crystalline silica gel that seeped into crevices in the sedimentary strata. Through time and nature's heating and molding processes, the gel hardened into the form of opals. The opal is composed of particles closely packed in spherical arrangements. When packed together in a regular pattern, a three-dimensional array of spaces are created that give opal its radiance. - See more at: There’s no better way to demonstrate your love than by giving a ruby in celebration of a July birthday. Rubies arouse the senses, stir the imagination, and are said to guarantee health, wisdom, wealth and success in love. Ruby is a variety of the gems species corundum. It is harder than any natural gemstone except diamond, which means a ruby is durable enough for everyday wear. Fine-quality ruby is extremely rare, and the color of the gem is most important to its value. The most prized color is a medium or medium dark vivid red or slightly purplish red. If the gem is too light or has too much purple or orange, it will be called a fancy-color sapphire.