Malachite Slab (#52)
|Africa||Shaba, Zaire||3 ½" x 2 ¼" x 1"|
This is known as banded malachite, for reasons that should be obvious. Specimens such as this one are chemical precipitates, deposited from an aqueous (water-rich) fluid. The exact cause of the banding is not known, and there may be more than one way in which it originates. Some mineralogists have observed that the lighter bands are formed of fine, fibrous crystals, while the darker ones consist of coarser crystals that may include some minerals other than malachite. Presumably, the growth conditions (temperature, level of saturation of the fluid, perhaps other factors) change erratically to form the bands. While a casual glance suggests that there are just two colors of banding, modest magnification reveals that there are different colors with in each band. The lighter bands, in particular, consist of very fine parallel bands of different shades of light green.
Polished banded malachite has been a popular ornamental stone from antiquity. Those who believe that certain minerals ("stones," as they call them) have mystical properties ascribe healing powers to malachite. Mineralogists would generally recommend seeing a physician for illness, rather than carrying or wearing a piece of malachite!