In Part 1 of my All About Macrocrystalline Quartz series we discussed the basics of Macrocrystalline Quartz: science, nomenclature, varieties, and uses.
In Part 2 we discussed Quartz crystal phenomena and inclusions present in Quartz crystals.
Now in Part 3 we will talk about the complicated world of formations and introduce terms both scientific and metaphysical.
Quartz Crystal Formation
Quartz crystals belong to the trigonal crystal system. Three equally long axes of the system of axes are horizontal and intersect at less than 120 degrees. The fourth axis, which can be longer or shorter, is vertical, intersecting the other three at a right angle.
The ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end. A crystal face is a natural surface, which is usually smooth, plane and reflective, unless it is marred by contact with other crystals or corrosive actions of solutions present during or after formation. Quartz crystals may be platy, acicular, short prismatic or bipyramidal. Aggregates (also known as Clusters) are irregular intergrowths of several crystals of the same kind. Quartz aggregates can be radiating fibrous, bladed or granular.
Most quartz forms in igneous rocks, but some quartz forms in environments with geothermal waters. In igneous rocks, quartz forms as magma cools. Silicon dioxide will crystallize as it cools. Slow cooling generally allows the crystals to grow larger. Quartz that grows from silica-rich water forms in a similar way. Silicon dioxide dissolves in water, like sugar in tea, but only at high temperature and pressure. Then, when the temperature or pressure drops, the solution becomes saturated, causing quartz crystals to form.
In nature quartz crystals are often twinned (with twin right-handed and left-handed quartz crystals), distorted, or so intergrown with adjacent crystals of quartz or other minerals as to only show part of this shape, or to lack obvious crystal faces altogether and appear massive.
Well-formed crystals typically form as a druse (a layer of crystals lining a void). Quartz geodes and Amethyst cathedrals are good examples. The crystals are attached at one end to the enclosing rock, and only one termination pyramid is present. However, double terminated crystals do occur where they develop freely without attachment, for instance in Herkimer Diamonds.
When the bottom of a Quartz Crystal is cut flat and it stands on its own it is referred to as a Crystal Point.
Quartz Crystal Habits
The habit of a mineral refers to the proportions of the individual faces in relation to each other or is its tendency to develop into different shapes under various conditions. Many of the commonly known names of these habits have been introduced and popularized by rockhounds or dealers.
The most well-known habits are:
Normal habit (or Prismatic habit): "Normal" quartz crystals that are not, or only slightly, tapered.
Trigonal habit: Crystals with obvious trigonal symmetry, for example, because of missing faces, or because of a triangular cross section, like in crystals with a Muzo habit (see below).
Hexagonal or Pseudohexagonal habit: Crystals with an even development of rhombohedral and prism faces, where the crystals show a hexagonal shape. Occurs in twinned crystals. Impurities interfere with crystal growth and quartz crystals with a lot of inclusions are often twinned. Thus, milky quartz or ferruginous quartz quite commonly shows a hexagonal habit.
Cumberland habit: Crystals with very small or absent prism faces, often bipyramidal.
Pseudocubic quartz: Crystals that look like slightly distorted cubes.
Dauphiné habit: Crystal tips with one or two very dominant rhombohedral face. This occurs because those faces grew slower than the rest of the crystal.
Tessin habit: A crystal whose hexagonal prism gets continuously thinner towards the tip of the crystal. They are tapered by steep rhombohedral faces. Tessin habit in the strict sense is dominated by faces.
Muzo habit: Crystals with prism faces that are tapered because of a succession of alternating faces, and who have a trigonal cross section at the crystal tips. In extreme cases the result is a crystal that does not show six but only three very steep prism faces. The cross section of the upper part of such crystals can be perfectly triangular, while the lower part of the crystals usually remains six-sided. The striations on the prism faces caused by the alternating types of faces can be barely or very visible.
Needle quartz (acicular habit): Needle quartz is simply the name for very elongated quartz crystals with a needle-like look.
Quartz Growth Forms
In addition to crystallographic forms and habits, many quartz crystals or aggregates are characterized by peculiar physical properties that reflect different modes of growth during their development. Some of these forms are found at many different localities and - like habits - have commonly known names that may have been originally coined by a rockhound or dealer!
Among the more well-known growth forms are:
Scepter Quartz: Crystals with syntaxial overgrowth of a second-generation tip that has a diameter greater than that of the original crystal. To be a scepter quartz, the second-generation quartz crystal must grow parallel to the underlying crystal. Whether the second generation grew on the old tip, sideways on the prism, or somewhere in between is not relevant.
Faden Quartz: Usually tabular crystals and crystal aggregates with a visible white “thread” running through the crystals. The thread is caused by repetitive cracking of the crystal during growth and consists of liquid and gas inclusions.
Window Quartz, Skeleton Quartz, Frame Quartz or Fenster Quartz: Crystals with naturally etched triangular formations or "windows" within the planes of the crystal, usually with parallel grown blades that grow from the edges to the center of the faces in a window glass-like manner.
Sprouting Quartz: Crystals on which smaller crystals sprout from the crystal faces. In most cases, the smaller crystals grow on the prism faces and are oriented roughly parallel to the central crystal, with the tips pointing slightly away from the crystal. These smaller crystals are second-generation on an older quartz crystal. This growth form resembles a candle with lots of wax dripping on its side, hence the name Candle Quartz or sometimes Celestial Quartz are other names used.
Artichoke Quartz: Similar to Sprouting Quartz, Artichoke Quartz has smaller attached crystals that resembles the arrangement of leaves on an artichoke head. The difference from Sprouting Quartz is the smaller crystals all point roughly to the same spot at the base. This is an indication that the smaller crystals of an Artichoke Quartz grew simultaneously, and not as a second generation, as in typical Sprouting Quartz. Also, the smaller crystals exhibit the same growth patterns and surface structures and look like miniature versions of Artichoke Quartzes.
Gwindel Quartz: Crystals grown “sideways”, elongated and twisted, along an a-axis in a platy crystal. These are very rare and only found in a few locations. They are always accompanied by "normal" quartz crystals and usually are slightly smaller than the other crystals.
Cactus Quartz, Pineapple Quartz or Spirit Quartz: Crystals whose prism faces are covered by small, roughly radially grown second-generation smaller crystals. Different from Candle Quartz because the small crystals point away from the prism.
Cathedral Quartz: When a central large crystal is surrounded by smaller, parallel grown crystals that are tightly attached to the central one, but not quite as tall, it is called a Cathedral Quartz.
Lemurian Seed Crystals: A rare type of Quartz from only one location- the Sierra Do Cabral Mountain in Minas Gerais, Brazil. These Crystals have etched striations (known as Akashic Lines) on all side facets. They may have a frosted look, but these crystals are usually very clear inside. Most of these crystals taper towards the tip and have small faces.
Some additional Metaphysical Crystal Point Formations:
Disclaimer-we are not metaphysical experts. There is lots and lots of information out there and many healers, dealers, authors, etc. have their own trade names for formations, as well as descriptions and information on how to use certain crystals in rituals. These are included for information purposes only and these seem to be the most well-known and accepted metaphysical terms:
Isis Quartz: An Isis crystal has a primary dominant face which is five sided with a tall sharp point. The two top sides of the face are longer than the three bottom ones.
Generator Quartz Crystals: The tips of all six faces must all meet together perfectly at the tip of the termination point in the center. The six faces are usually triangular shapes of similar size, but not always.
Window or Diamond Window: An extra face or “window” in clear quartz or a coated quartz with a clear spot where you can see inside the crystal. A Diamond Window has a small diamond shaped window face between, and slightly lower than, the six main faces.
Record Keeper: The Record Keeper quartz crystal has raised triangles that appear on the main facets of the stone’s terminations.
Grounding Quartz: A Grounding Quartz crystal has a primary dominant face which is eight sided.
Channeling Quartz: A Channeling Quartz crystal has a primary dominant face which is seven sided.
Laser Wands: Long, tapered crystals with small terminations.
I've enjoyed exploring the world of Quartz. I hope you have enjoyed it to!