The random letter believe it or not was "Q".  I could think of no better mineral than one of the most common ones there is.  Besides being my favorite, with respect to growth forms, colors, and habits, I believe it's one of the most diverse and beautiful minerals on the planet.  Behold, quartz.

Quartz is the second most abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2.

There are many different varieties of quartz, several of which are semi-precious gemstones. Especially in Europe and the Middle East, varieties of quartz have been since antiquity the most commonly used minerals in the making of jewelry and hardstone carvings.

Etymology

The word "quartz" is derived from the German word "Quarz" and its Middle High German ancestor "twarc", which probably originated in Slavic (cf. Czech tvrdý ("hard"), Polish twardy ("hard")).[6]

Crystal habit and structure

Quartz belongs to the trigonal crystal system. The ideal crystal shape is a six-sided prism terminating with six-sided pyramids at each end. In nature quartz crystals are often twinned, 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 in a 'bed' that has unconstrained growth into a void; usually the crystals are attached at the other end to a matrix and only one termination pyramid is present. However doubly-terminated crystals do occur where they develop freely without attachment, for instance within gypsum. A quartz geode is such a situation where the void is approximately spherical in shape, lined with a bed of crystals pointing inward.

α-quartz crystallizes in the trigonal crystal system, space group P3121 and P3221 respectively. β-quartz belongs to the hexagonal system, space group P6222 and P6422, respectively.[7] These space groups are truly chiral (they each belong to the 11 enantiomorphous pairs). Both α-quartz and β-quartz are examples of chiral crystal structures composed of achiral building blocks (SiO4 tetrahedra in the present case). The transformation between α- and β-quartz only involves a comparatively minor rotation of the tetrahedra with respect to one another, without change in the way they are linked.

Varieties (according to color)

Pure quartz, traditionally called rock crystal (sometimes called clear quartz), is colorless and transparent (clear) or translucent, and has often been used for hardstone carvings, such as the Lothair Crystal. Common colored varieties include citrine, rose quartz, amethyst, smoky quartz, milky quartz, and others. Quartz goes by an array of different names. The most important distinction between types of quartz is that of macrocrystalline (individual crystals visible to the unaided eye) and the microcrystalline or cryptocrystalline varieties (aggregates of crystals visible only under high magnification). The cryptocrystalline varieties are either translucent or mostly opaque, while the transparent varieties tend to be macrocrystalline. Chalcedony is a cryptocrystalline form of silica consisting of fine intergrowths of both quartz, and its monoclinic polymorph moganite.[8] Other opaque gemstone varieties of quartz, or mixed rocks including quartz, often including contrasting bands or patterns of color, are agate, sard, onyx, carnelian, heliotrope, and jasper.

Citrine

Citrine is a variety of quartz whose color ranges from a pale yellow to brown due to ferric impurities. Natural citrines are rare; most commercial citrines are heat-treated amethysts or smoky quartzes. However, a heat-treated amethyst will have small lines in the crystal, as opposed to a natural citrine's cloudy or smokey appearance. It is nearly impossible to tell cut citrine from yellow topaz visually, but they differ in hardness.Brazil is the leading producer of citrine, with much of its production coming from the state of Rio Grande do Sul. The name is derived from Latin citrina which means "yellow" and is also the origin of the word "citron." Sometimes citrine and amethyst can be found together in the same crystal, which is then referred to as ametrine.[9]

Rose quartz

Rose quartz is a type of quartz which exhibits a pale pink to rose red hue. The color is usually considered as due to trace amounts of titanium, iron, or manganese, in the massive material. Some rose quartz contains microscopic rutile needles which produces an asterism in transmitted light. Recent X-ray diffraction studies suggest that the color is due to thin microscopic fibers of possibly dumortierite within the massive quartz.[10]

Additionally, there is a rare type of pink quartz (also frequently called crystalline rose quartz) with color that is thought to be caused by trace amounts of phosphate or aluminium. The color in crystals is apparently photosensitive and subject to fading. The first crystals were found in a pegmatite found near Rumford, Maine, USA, but most crystals on the market come from Minas Gerais, Brazil.[11]

Amethyst

Amethyst is a popular form of quartz that ranges from a bright to dark or dull purple color. The world's largest deposits of amethysts can be found in Brazil, Mexico, Uruguay, Russia, France, Namibia and Morocco. Sometimes amethyst and citrine are found growing in the same crystal. It is then referred to as ametrine. An amethyst is formed when there is iron in the area where it was formed.

Smoky quartz

Smoky quartz is a gray, translucent version of quartz. It ranges in clarity from almost complete transparency to a brownish-gray crystal that is almost opaque. Some can also be black.
Various smoky quartz examples from NC:  http://www.rockhoundlounge.com/cgi-bin/yabb252/YaBB.pl?num=1297482529

Milky quartz

Milk quartz or milky quartz may be the most common variety of crystalline quartz and can be found almost anywhere. The white color may be caused by minute fluid inclusions of gas, liquid, or both, trapped during the crystal formation. The cloudiness caused by the inclusions effectively bars its use in most optical and quality gemstone applications.[12]

Varieties (according to microstructure)

Although many of the varietal names historically arose from the color of the mineral, current scientific naming schemes refer primarily to the microstructure of the mineral. Color is a secondary identifier for the cryptocrystalline minerals, although it is a primary identifier for the macrocrystalline varieties. This does not always hold true.[clarification needed]

Major varieties of quartz

Chalcedony	Cryptocrystalline quartz and moganite mixture. The term is generally only used for white or lightly colored material. Otherwise more specific names are used.
Agate	Multi-colored, banded chalcedony, semi-translucent to translucent
Onyx	Agate where the bands are straight, parallel and consistent in size.
Jasper	Opaque cryptocrystalline quartz, typically red to brown
Aventurine	Translucent chalcedony with small inclusions (usually mica) that shimmer.
Tiger's eye	Fibrous gold to red-brown colored quartz, exhibiting chatoyancy.
Rock crystal	Clear, colorless
Amethyst	Purple, transparent
Citrine	Yellow to reddish orange to brown, greenish yellow
Prasiolite	Mint green, transparent
Rose quartz	Pink, translucent, may display diasterism
Rutilated quartz	Contains acicular (needle-like) inclusions of rutile
Milky quartz	White, translucent to opaque, may display diasterism
Smoky quartz	Brown to gray, opaque
Carnelian	Reddish orange chalcedony, translucent
Dumortierite	quartz Contains large amounts of dumortierite crystals

Synthetic and artificial treatments

A synthetic quartz crystal grown by the hydrothermal method, about 19 cm long and weighing about 127 grams
Not all varieties of quartz are naturally occurring. Some clear quartz crystals can be treated using heat or gamma-irradiation to induce color where it would not otherwise have occurred naturally. Susceptibility to such treatments depends on the location from which the quartz was mined.[13] Prasiolite, an olive colored material, is produced by heat treatment; natural prasiolite has also been observed in Lower Silesia in Poland. Although citrine occurs naturally, the majority is the result of heat-treated amethyst. Carnelian is widely heat-treated to deepen its color.

Because natural quartz is often twinned, synthetic quartz is produced for use in industry. Large, flawless, single crystals are synthesized in an autoclave via the hydrothermal process; emeralds are also synthesized in this fashion.

Occurrence

Quartz is an essential constituent of granite and other felsic igneous rocks. It is very common in sedimentary rocks such as sandstone and shale and is also present in variable amounts as an accessory mineral in most carbonate rocks. It is also a common constituent of schist, gneiss, quartzite and other metamorphic rocks. Because of its resistance to weathering it is very common in stream sediments and in residual soils. Quartz, therefore, occupies the lowest potential to weather in the Goldich dissolution series.

While the majority of quartz crystallizes from molten magma, much quartz also chemically precipitates from hot hydrothermal veins as gangue, sometimes with ore minerals like gold, silver and copper. Large crystals of quartz are found in magmatic pegmatites. Well-formed crystals may reach several meters in length and weigh hundreds of kilograms.

Naturally occurring quartz crystals of extremely high purity, necessary for the crucibles and other equipment used for growing silicon wafers in the semiconductor industry, are expensive and rare. A major mining location for high purity quartz is the Spruce Pine Gem Mine in Spruce Pine, North Carolina, United States.[14]

The largest documented single crystal of quartz was found near Itapore, Goiaz, Brazil; it measured approximately 6.1×1.5×1.5 m and weighed more than 44 tonnes.[15]

Related silica minerals

Tridymite and cristobalite are high-temperature polymorphs of SiO2 that occur in high-silica volcanic rocks. Coesite is a denser polymorph of quartz found in some meteorite impact sites and in metamorphic rocks formed at pressures greater than those typical of the Earth's crust. Stishovite is a yet denser and higher-pressure polymorph of quartz found in some meteorite impact sites. Lechatelierite is an amorphous silica glass SiO2 which is formed by lightning strikes in quartz sand.

History

Fatimid carved rock crystal (clear quartz) vase, c. 1000

The word "quartz" comes from the German About this sound Quarz (help·info),[16] which is of Slavic origin (Czech miners called it křemen). Other sources attribute the word's origin to the Saxon word Querkluftertz, meaning cross-vein ore.[17]

Quartz is the most common material identified as the mystical substance maban in Australian Aboriginal mythology. It is found regularly in passage tomb cemeteries in Europe in a burial context, such as Newgrange or Carrowmore in Ireland. The Irish word for quartz is grian cloch, which means 'stone of the sun'. Quartz was also used in Prehistoric Ireland, as well as many other countries, for stone tools; both vein quartz and rock crystal were knapped as part of the lithic technology of the prehistoric peoples.[18]

While jade has been since earliest times the most prized semi-precious stone for carving in East Asia and Pre-Columbian America, in Europe and the Middle East the different varieties of quartz were the most commonly used for the various types of jewelry and hardstone carving, including engraved gems and cameo gems, rock crystal vases, and extravagant vessels. The tradition continued to produce objects that were very highly valued until the mid-19th century, when it largely fell from fashion except in jewelry. Cameo technique exploits the bands of color in onyx and other varieties.

Roman naturalist Pliny the Elder believed quartz to be water ice, permanently frozen after great lengths of time.[19] (The word "crystal" comes from the Greek word κρύσταλλος, "ice".) He supported this idea by saying that quartz is found near glaciers in the Alps, but not on volcanic mountains, and that large quartz crystals were fashioned into spheres to cool the hands. He also knew of the ability of quartz to split light into a spectrum. This idea persisted until at least the 17th century.

In the 17th century, Nicolas Steno's study of quartz paved the way for modern crystallography. He discovered that regardless of a quartz crystal's size or shape, its long prism faces always joined at a perfect 60° angle.[20]

Quartz's piezoelectric properties were discovered by Jacques and Pierre Curie in 1880.[21] The quartz oscillator or resonator was first developed by Walter Guyton Cady in 1921.[22][23] George Washington Pierce designed and patented quartz crystal oscillators in 1923.[24][25] Warren Marrison created the first quartz oscillator clock based on the work of Cady and Pierce in 1927.[26]

wikipedia source page:  http://en.wikipedia.org/wiki/Quartz

Some information on the formation of quartz crystals and history of quartz crystal collection in the southeast from;

"Quartz Crystal Deposits of Southwestern Virginia and Western North Carolina"
by John B. Mertie, Jr.  1949.

"All the quartz deposits are in areas where the bedrock is dominantly schist or gneiss, in which are many veins and lenticular bodies of opaque white quartz; but it believed that these veins are not the source of, and have no genetic relationship to, the deposits of quartz crystals.
Three modes of formation of quartz crystals are recognized: first, primary fillings of fissures, vugs, solution cavities, and other open spaces; second, hypogene crystals, of primary or secondary origin, in pegmatites, particuarly in vugs or banded zones, and third; supergene crystals of quartz that grew in bedrock during or after the time when the latter was decomposed by weathering to saprolite. Many, if not most, of the quartz crystals in the areas studied are believed to have originated by the third method, and to such crystals, the designation "pocket quartz" is applied."
"Both the quartz crystals and the vein quartz have been concentrated at the surface of the ground and in the upper part of the soil as a result of long continued residual weathering. Such concentrations do not necessarily indicate that other quartz of the same kind lies directly below in bedrock; on the contrary, such deposits are more likely to indicate that the veins, dikes, and supergene pockets have been eroded, to form the surficial deposits."

"These older rocks are cut by many veins and lenticular masses of quartz, most of which is of the opaque white variety, often designated by mining men as "bull quartz". The age of such quartzis of the same order of magnitude as the schistose and gneissoid country rocksin which it occurs. Hereafter the opaque white quartz within these veins and lenses is designated as the older or ancient quartz."

So, I must say that I do not compeltely understand how the Type 3 quartz crystals are formed even though the description can be plainly seen in most of our local areas.
I have noticed that the main crystallization in most areas seems to be closer to the surface. Also, just because you see quartz on the surface does not mean it continues deeper below the surface.

Finally, from the Introduction of this report, a little about the history and use of quartz crystals.

" Crystals of quartz are sliced into thin plates that are used extensively as oscillators, mainly in high-frequency electric circuits; but such plates are also used to a lesserextent as low-frequency oscillators, and as filters in high and low-frequency communication systems. The principal function of oscillating quartz crystal plates is to stabilize the frequency of electric waves that are being radiated from transmitters, though they are also used in telegraphic receivers. Quartz crystals were first used commercially as frequency stabilizers by radio station WEAF in New York in 1926.
Most of the quartz thus utilized in the United States has come from Brazil. Prior to World War II, an adequate supply of crystals was not difficult to obtain, but the war quickly changed this condition. The fighting equipment of the United States armed forces was multiplied many times within ashort period, and much of this equipment required radio transmitters that used crystal oscillators. As a result of these unusual demands a shortage of suitable crystals developed; and this shortage was rendered more acute by the submarine blockade of shipping between Brazil and the United States. In the meanwhile, however, every effort was made by the U.S. Geological Survey to discover and appraise the quartz deposits of the United States, and the present paper describes the results of this appraisal in the southeastern Atlantic States."

Because of twinning, tectonics, inclusions and impurities oscillator quality quartz is very rare in nature. By 1950 most oscillator quartz plates were being created in the lab.

Here are a few of my favorites I found

Here's a few of my favorites.

Chatham Co.




Randolph Co.


Wake Co.

awesome lighting job on that top one scott, its fantastic! amazing how the crust eases up on all of the edges

Yeah, but does he have one of these?
An Intergalactic Alien Transmitter/Receiver,
Dormant and...... Activated

FireOnTheMountain wrote on Feb 16^th, 2015 at 6:05pm:

Thanks!  It's always a joy pulling them out to look at them on a rainy day.


dave wrote on Feb 17^th, 2015 at 10:57am:

Thanks Dave.  Yeah, it was as if the crystal continued growing after the white coating was distributed so it got too big for its britches. 


Quote:


Thanks Laurie, I was blessed and privileged to get to know great rockhounds such as yourself, Joe Moylan, Dave Hart, Rob Whaley, and Bob Crocker who have all shown me awesome locations and taught me a lot along the way.

Awesome pic, Scott. Thanks for the follow-up.
It is interesting how "different" the etching is on the termination surfaces
compared to the sides. The sides are so etched it still looks like a coating.