Rutile, titanium dioxide, is a common mineral and sometimes is even a major component of beach sand. It is the major source of the element titanium, a strategic metal with unique properties. Rutile is red, but crystals can be so thick as to appear black. The lovely reticulated (lace-like) aggregates from Boiling Springs, North Carolina are not typical formations. Rutile crystals are generally primsatic, but also can be acicular (needle-like) and when overgrown by clear quartz the result is rutilated quartz, a popular gem material.