Physical Properties Of Quartz

(1) Brittle.
(2) Exhibits pyroelectric properties.
(3) Refractive index: 1.533–1.541; birefringence: 0.009; dispersion: 0.013.
(4) Quartz exhibits strong piezoelectric properties; specifically, striking or rubbing it forcefully generates sparks-a principle utilized in making fire with flint.
(5) Common inclusions in quartz include: "Hair crystal" (rutilated quartz)-primarily rutile; "Grass-in-crystal"-primarily tourmaline; "Water-bubble crystal" (enhydro quartz)-containing liquid inclusions; "Blue quartz"-containing pale blue needle-like rutile inclusions; "Milky quartz"-appearing cloudy due to minute fluid-filled cavities; "Green quartz"-containing platy or fragmented chlorite, or sometimes green needle-like actinolite; "Aventurine"-quartzite containing fine flakes of green or reddish-brown mica (also known as glittering quartz or "Dongling stone"). Smoky quartz (ranging from smoky black to dark brown) is also common; this coloration is primarily due to the presence of radioactive elements such as uranium and thorium within the rock.