Introduction

Bixi is a kind of mid-grade gem and its mineralogical name is tourmaline.

Crystalline: ditrigonal prism shape; on its surface, along the extension of the columnar prism, there are featured growth striations; on the cross section, it appears spherical triangle with curved surface.

Color: the color of the tourmaline is the most abundant in various gems. Tourmaline is a kind of complex borosilicate mineral, and its chemical formula is Na (Mg, Fe, Mn, Li, Al)3 Al6 [Si6O18][BO3]3(OH,F)4; the metal ion of Fe, Mg, Li, Mn and Al can be replaced by each other. The content of the ions can influence the color of the tourmaline directly. Fe –rich tourmaline appears black or green; Mg-rich tourmaline appears yellow or brown; Li-rich, Mn-rich and Cs-rich tourmaline appears rosy, pink, red or blue; Cr-rich tourmaline appears dark green. Top-grade tourmaline appears sky-blue and rose red.  Because of the uneven distribution of the elements, there are always color changes on the same crystalline; there is bi-colored tourmaline, multi-colored tourmaline or watermelon tourmaline with red inside and green outside and other kinds.

Vitreous luster, transparent to translucent, refractive index: 1.624-1.644, birefractive index: 0.018-0.040, chromatic dispersion: 0.017, polychroism, hardness: 7-7.5, density: 3.06-3.26g/cm3, no cleavage, conchoidal fracture.

Piezoelectricity and thermoelectricity: when heated or exerted pressure, or rubbed with silk or wollens, tourmaline has electrode effect on both ends, one end with positive, the other end with negative, and tourmaline can suck some dust or scraps of paper, and this magic strength is the piezoelectricity and thermoelectricity, and this is the reason why this kind of mineral is called “tourmaline”.

Black Bixi (black tourmaline)

Black tourmaline is black, appearing profound.

1. It can relieve stress and fatigue, discharge foul air, improve health and boost luck.

2. For those who are vulnerable to timorousness during the sleep and have nightmares, black tourmaline has the effect to stable the space energy and drive away evil spirits.

3. It can help patients be free from outside interference and recuperate quickly.