As crystals grow they are very sensitive to their environment. Subtle changes in temperature, pressure and chemistry can create changes in the crystals growth. This group of photos depicts some of the imperfections associated with Quartz.
Growth Hillocks - These triangular shaped
growths are commonly found on the pyramid faces of quartz crystals from Diamond
Point, Arizona (as well as other places). They are produced when
microscopic dislocations develop on the crystal face. This dislocation
produces an active growth area that produces these bumps on the pyramid faces.
Inclusions are another type of
imperfection. This quartz crystal contains abundant grains of the mineral
Hematite, thus its reddish color.
Inclusions of hematite in these quartz
crystals from Thunder Bay, Ontario, Canada.
Phantoms in crystals are produced when the
growing crystal is dusted with another material. It could be clay or some
other mineral deposit. The crystal, however, continues to grow including
the coating and preserving this earlier growth stage.
Selected incrustations occur when typically
fine grained minerals coat another mineral. The electrical properties of
the host mineral often allow for coatings in certain directions or on certain
faces.
Phantom quartz was formed when chlorite
crystals covered and earlier growth stage of this crystal.
Solid inclusions of Rutile
Scepter crystals of quartz develop when the
pyramidal faces of crystal enlarge. Very often the scepter tip is more
"gemmy" than the rest of the crystal and is frequently amethystine.
Striations - This imperfection is the result
of a competition between crystal faces. Seen here on the prism faces the
horizontal lines are actually pyramid faces producing a small, but distinct,
step. These striations can be very obvious as in this photo or nearly
invisible.
Faden - A type of twin