The chemical formula of mineral Sanbornite is indicated by BaSi2O5 or Barium Silicate. Sanbornite is actually a Silicate mineral. Sanbornite is only most commonly used as mineral specimen. Sanbornite is only one of the few barium minerals. Sanbornite is most commonly found pale green in color that can be more splendidly exhibited when viewed under polarized microscope used in the field of optical mineralogy. It can be also found gray, white or colorless. Sanbornite is most commonly found showing pearly to vitreous or dull luster when viewed in reflected light of petrographic polarizing light microscopes used in the field of optical mineralogy. The crystals of mineral Sanbornite are usually found transparent to mostly translucent in appearance. Sanbornite is known to crystallize in the orthorhombic system of crystal formation. In optical mineralogy, this orthorhombic crystal system comprises crystals having three mutually perpendicular axes, of which all are of different lengths.             The crystal habit of mineral Sanbornite as described in the field of optical mineralogy usually include flat tabular or lamellar crystals that can be more interesting when viewed under petrographic polarizing light microscopes for mineralogists. Sanbornite is also showing good cleavage in one direction when viewed under polarized microscope. It also exhibits uneven fracture when evaluated with the aid of polarizing microscopes used in optical mineralogy. The hardness measure of mineral Sanbornite when it is evaluated using the Mohs scale method is usually found 5. Sanbornite is most commonly found leaving a white streak when specimen is rubbed on a white porcelain streak plate. The specific gravity measure of the mineral Sanbornite is approximately 3.8 grams per cubic centimeters, which is above average for a non-metallic mineral. Sanbornite also displays iridescence between cleavage layers and lamellar twinning when viewed with the aid of polarized microscopes used in the field of optical mineralogy. the best field indicator of mineral Sanbornite usually include locality, crystal habit, hardness, color and cleavage. Sanbornite has limited occurrence at Trumball Peak, Mariposa County and Big Creek, Fresno County, California, USA.