schorl การใช้

• The formation is predominantly Precambrian granite with outcroppings of quartz and schorl.
• Associated minerals include quartz, potassium feldspar, muscovite, schorl, riebeckite and magnesite.
• Elbaite forms three series, with dravite, with fluor-liddicoatite, and with schorl.
• Opaque black schorl and yellow tsilaisite are idiochromatic tourmaline species that have high magnetic susceptibilities due to high concentrations of iron and manganese respectively.
• Elbaite tourmalines are allochromatic, deriving most of their color and magnetic susceptibility from schorl ( which imparts iron ) and tsilaisite ( which imparts manganese ).
• Tourmaline hornfels are found sometimes near the margins of tourmaline granites; they are black with small needles of schorl that under the microscope are dark brown and richly pleochroic.
• In the pegmatite veins one finds well developed garnets ( grain size 2 millimeters ), millimetric tourmaline ( schorl ) and asparagus-coloured apatite reaching 5 millimeters in size.