You will get one of the Black Onyx Sphere similar to the one in the listing, the size and the color of the sphere may slightly vary as well due to the fact that all minerals are different. (see photo, the photos are taken under bright light, stand included)! Average 1pc Weight 185g / 6.5oz; Average 1pc Size 50mm / 2 Inches; Originally, almost all colors of chalcedony from white to dark brown and black were called onyx. Today when we think of onyx we often preface the word with black to distinguish it from other varieties of onyx that come in white, reddish brown, brown and banded. A variety of onyx that is reddish brown with white and lighter reddish bands is known as sardonyx. Chemical Formula: SiO2; Mohs scale hardness: 6.5–7; Color: black; Onyx is formed of bands of chalcedony in alternating colors. It is cryptocrystalline, consisting of fine intergrowths of the silica minerals quartz and moganite. Its bands are parallel to one another, as opposed to the more chaotic banding that often occurs in agates. (The above information is provided solely for informational purpose. Kindly note that all stones are offered for decorative purposes only. Please, handle your stones with great care, do not grind or crumble them, do not dip or add them into your food or drink, do not use any parts of them in any elixirs, potions, lotions etc. Always make sure you wash your hands before and after working with your crystals.) All our minerals and crystals are carefully measured with digital measuring instruments that provide the high accuracy of numbers/values!