Quartz: characteristics, types, colors, properties and uses


Quartz is a crystal of a thousand colors, shapes and varieties. Blue, pink, purple, white, green types of quartz are used to create beautiful colored jewels, to make watches, lamps, digital appliances, light bulbs, bathroom furniture and much more also thanks to its physical properties very useful in the industrial field. Some varieties of quartz rock are transparent like a piece of ice. Hence, quartz meaning, according to some scholars, comes from ancient Greek word “krýstallos“, that is, precisely, ice: in fact, they thought that quartz was a kind of ice that, for some reason, could no longer melt and become water again; belief deriving from the fact that clear quartz in addition to being cold to the touch, also resembled snowflakes in its structure. There are many legends and stories that revolve around precious quartz stone: many ancient peoples believed that quartz had magical and even therapeutic properties. In short, quartz has a history that has its roots in prehistoric times: our ancestors used it to build knives, axes, cutting tools and tips for arrows and spears, as well as to create jewels, pendants and precious amulets of various kinds, even used during religious ceremonies.

Characteristics of quartz

characteristics of quartz

Quartz is one of the most widespread and common minerals in the earth’s crust which is mined in many areas of the world. It is very common to find quartz rock on the banks of rivers and lakes or along the slopes of volcanoes following a crystallization process during the cooling of lava material. Quartz is one of the main elements that make up many types of rocks, namely igneous, sedimentary and metamorphic ones. From a chemical point of view, quartz stone corresponds to silicon dioxide (SiO2), that is formed by the combination of one part of silicon and two parts of oxygen that form tetrahedrons and are divided into three categories: macrocrystalline quartz when crystals quartz are visible to the naked eye (like rose quartz); microcrystalline quartz when crystals quartz can only be seen under the microscope (such as jade) and cryptocrystalline quartz when crystals quartz are not even seen under a microscope (such as chalcedony). Clear quartz has a density of 2.65 g/cm3 and from a thermal point of view it has a stable shape below 573 °C. Quartz is a hard mineral that on the Mohs scale measures 7, while the diamond 9, and is therefore harder than metal. Clear quartz has a vitreous and reflective luster and, in its purest form, it is transparent, clear and colorless and often, depending on the geological zone in which it is located, can contain gaseous, solid and liquid inclusions.

From a crystallographic point of view, quartz has a trigonal lattice and has a six-sided bipyramidal prism-shaped habitus but it is very rare to find it in this form and is generally found as small grains within metamorphic and magmatic rocks. However, quartz stone can also be in the shape of an elongated prism. Among its most important properties and characteristics, quartz has a remarkable stability and is resistant to any type of acid, except hydrofluoric acid. Furthermore, it is resistant to heat and breakage and it is piezoelectric, which means that it can electrically polarize its opposite faces after a process of mechanical deformation caused by heating or compression.

Quartz colors

Since it is one of the most widespread minerals in the world, quartz has, depending on the geological zone of formation, a crystalline structure and different mineralogical and chemical characteristics, with numerous shades of quartz color. When pure, clear quartz is completely transparent and colorless. When it has impurities, defects or inclusions of other rocks and minerals, this mineral begins to take on different quartz colors. Carnelian, a particular type of red chalcedony, for example, takes on this color due to the presence of iron oxides inside, as does amethyst which has a more or less transparent color tending to purplish; green quartz which contains lamellar inclusions or like jasper which is opaque and very colored due to the presence of impurities. Citrine quartz rock, on the other hand, is yellow due to the presence of iron impurities; chrysoprase is apple green due to the presence of nickel and hydrated salts and so on. In short, depending on the chemical structure and the contamination of other minerals, the ice-colored clear quartz can turn into many and different stones of many and beautiful quartz colors.

Purple quartz: Amethyst

purple quartz amethyst

A beautiful gem used mostly to make jewelry, amethyst quartz is a variety of purple quartz that takes on this hue due to the presence of iron in its crystal lattice. Its name seems to derive from the ancient Greek “Amethystos” or “not drunk”. This derives from a legend that sees as the protagonist the god of wine Bacchus who used to vent his anger on human beings when he was inebriated. One day he broke his anger on a young disciple named Amethyst by having her attacked by tigers. Artemis, goddess of the hunt, in order to defend the young woman, decided to transform her into a quartz stone statue which Dionysus then bathed with his cup of wine, transforming it into purple quartz which will later take its name from the young woman, Amethyst.

Purple quartz is the stone commonly associated with the purple color even if in nature there are many other varieties such as tanzanite and sapphire. Purple quartz color can be more or less intense depending on the composition of the crystalline habitus and the amount of iron: the more colored the stone, the greater its value. When it is brought to a temperature of over 450°C, the amethyst quartz changes color, becoming first yellow, then orange and finally brown.

Amethyst quartz crystals are bright and shiny and can have different shapes, so much so that it is possible to find it both as a single stone and in druse, that is a grouping of crystals implanted on a single portion of rock. The main quartz deposits are found all over the world and especially in Brazil, Mexico, USA, India and Bolivia; but also in northern Italy, especially in the provinces of Trento, Turin, Bolzano and Grosseto.

Rose quartz

rose quartz

What is rose quartz? Undisputed symbol of femininity, love, compassion and sensitivity; rose quartz is the most used stone of all in crystal therapy treatments, a discipline of ancient Indian origins that promises to absorb the negative energy of the body and rebalance physical and mental well-being through the use of gems and crystals.

As far as the chemical composition of rose quartz is concerned, it belongs to the previously described group of macrocrystalline quartz, composed, that is, of silicon dioxide, whose crystals are visible to the naked eye. Like all quartz in this category, it is formed in pegmatitic or lava rocks and has the property of piezoelectricity. Rose quartz meaning comes from its beautiful pink color, which can vary becoming more or less intense depending on the inclusions of other minerals. When the quartz is of a more charged but opaque pink color, it means that inclusions of dumortierite, a beautiful vitreous mineral with variable colors, such as red, purple, blue and green, have occurred in rose quartz crystal lattice. When, on the other hand, rose quartz is of a very bland, almost transparent and translucent pink, it means that there have been inclusions of phosphorus and aluminum and this is the rarest variety to find and therefore much more valuable and sought after. Thanks to its brilliance capable of reflecting light and shining in the sun, of its undisputed elegance and beauty, rose quartz is used a lot as a gem to create a rose quartz necklace, rose quartz ring, rose quartz bracelet, rose quartz earrings and various jewels and according to legend, it is a gift from the god Eros to men.

Citrine quartz: yellow quartz

Citrine quartz is a variety of crystalline quartz with calcium dioxide ranging in color from yellow to red to orange. The color of citrine quartz is due to the presence in its crystal lattice of traces, more or less intense, of iron in the trivalent form. Compared to amethyst, yellow quartz changes the oxidation state of iron and it is quite rare to find it pure in nature as most of the citrine quartz types on the market are nothing more than amethyst quartz varieties chemically treated until they reach the characteristic yellow or orange color or through a smoky quartz smoking process. Citrine quartz is found in volcanic and pegmatitic rocks, often in deep cavities and the main deposits are found in Bolivia, Brazil, USA and Madagascar. As for the price, yellow quartz is quite cheap and can range from € 10 to € 100 per carat, which can increase depending on the color, clarity and brilliance of the stone. For example, a citrine quartz without imperfections and an intense orange color can exceed € 100, but in its natural shapes and colors, it is a gem with an excellent quality-price ratio. In addition to its chemical characteristics, citrine quartz also has magical properties. In fact, according to crystal therapy, yellow quartz produces beneficial effects both on the body by stimulating the activity of the spleen, kidneys, nervous and immune systems, and on the mind, increasing self-esteem, safety, tranquility and helps to discharge the negative emotions and to combat sadness and depression.

Rock crystal: hyaline quartz

Hyaline quartz, also called rock crystal or mountain crystal, is a variety of very pure, colorless quartz and, usually, unlike milky quartz, perfectly transparent and therefore free of inclusions. The most widespread quartz stone on earth, rock crystal has deposits that are widespread all over the world: in Russia, Canada, Germany, India and especially in Brazil. It is found inside plutonic rocks filled with hydrothermal waters rich in silicon oxide. A lava stone with a thousand magical and chemical qualities, quartz occurs in nature in both microcrystalline and macrocrystalline forms. As for the price, it varies according to purity, size, shape and cut, but all in all it does not tend to exceed € 50. Hyaline quartz can be easily found in jewelry and costume jewelry stores but also on the internet or in herbalist shops, in this case sold and marketed by virtue of its therapeutic properties on the body, mind and spirit, capable of improving meditation, relieving physical pains and balance energies, especially male ones.

Green quartz: chrysoprase

Green quartz, scientifically called chrysoprase, is a variety of chalcedony that contains nickel inclusions in its crystal lattice that give it its particular apple green color. However, the color may vary depending on the impurities, ranging from mint green to light brown. Furthermore, green quartz lightens when exposed to the sun or stored in very hot places, but can easily return to its natural state if placed underground or in humid places.

Chrysoprase (green quartz) is a variety of cryptocrystalline quartz, which is composed of crystals so thin that they are impossible to see even under a microscope. On the Mohs scale, it has a hardness of 6-7, therefore slightly softer than the other varieties. Green quartz is found in deposits all over the world: in Russia, Poland, South Africa, India, USA, Germany, Madagascar and especially in Australia, specifically in central Queensland where the best specimens are found in terms of purity and size. Like all other stones, green quartz according to crystal therapy also produces numerous effects on the body and mind: it frees the psyche from obsessions by helping against addictions and fears, stimulates the correct activity of the liver and nervous system, prevents allergies and fights both female and male infertility problems.

Smoky quartz: brown, gray and black

Smoky quartz has a color that can vary from brown to gray up to black. Raw smoky quartz was born as a pure and colorless crystal but undergoes a process of natural or artificial radiation with radioactive materials such as uranium and thorium and owes its color also thanks to the inclusions of aluminum and blond rutile or copper. The color gradation of smoky quartz, from light brown to black, varies according to the duration of radiation exposure. The clearest variety of smoky quartz, dark yellow-light brown or gray-brown in color, takes the name of Cairngorm, from the name of the homonymous mountains in which it is found in abundance in Scotland. The opaque black variety of smokey quartz is called Morion or black quartz and is found mainly in France. Smoky quartz properties are, according to crystal therapy, the improvement of the survival instinct, release of stress and meditation support.

Rutilated quartz

Rutilated quartz gets its name because its crystal lattice contains rutile quartz crystals, or titanium dioxide with large amounts of iron oxide in a needle-like form that can be red, gold, silver or green in its rarest forms. When the iron content is very high, the needles have a lighter color (golden rutilated quartz), while when the levels are lower, they have a very dark, almost black color (black rutilated quartz). The typical appearance of this gem is that of a hyaline or smoked quartz with thin thread-shaped inclusions generally golden.

Rutilated quartz, thanks to its beautiful streaks, is also called “Hair of Venus“, a name that derives from the Middle Ages and the belief that the stone can slow down aging. One of the most important characteristics of rutilated quartz is that it has a high refractive index compared to other minerals. It is born inside the earth, in igneous or pegmatitic rocks and on the Mohs scale it has an average hardness of 7, like all types of quartz of its variety. The deposits in which rutilated quartz are hidden are essentially found in Brazil, Madagascar, Switzerland and India. It is a much rarer variety and therefore more expensive than the other more common types. According to crystal therapy rutilated quartz also has magical and even esoteric properties: rutilated quartz is considered a very powerful psychic stone, capable of fighting eating disorders and promoting the absorption of food, but also capable of fighting depression, sadness and anxiety.

Quarts uses

Quartz is not only a gem capable of embellishing necklaces or rings, but it is a stone with a thousand uses. Beyond purely ornamental purposes, quartz rock is also used in the technological field for the production of light bulbs, lenses, abrasives, glass, coatings and flooring. It is the raw material of the electronics industry and is used to produce all kinds of digital devices such as batteries, processors and much more. Furthermore, quartz in microgranules is used to make quartz paint, used for external surfaces thanks to its numerous properties. In short, the uses of clear quartz are truly innumerable, in addition to merely decorative and aesthetic ones.

Quartz bathroom

Quartz stone is a truly versatile material and extremely elegant and refined, if wisely used. One of the most charming applications is surely that of quartz installed inside the bathroom. The best solutions are the realization of a wonderful quartz bathtub or shower (for instance the shower can be embellished by luxurious quartz shower walls). Another scenographic creation, unique in its genre, is surely the backlit quartz sink and quartz vanity tops, for an incredible relaxing and warm effect.

Quartz countertops

Kitchen manufacturers often offer a quartz countertop. Quartz countertops are tops composed of agglomerates of resins and quartz powders, available in various colors. This material surprises not only for its remarkable aesthetic impact capable of giving elegance and prestige to the kitchen, but also because it is extremely convenient in terms of resistance, versatility and durability. The great quality of using quartz for this application is also versatility and wide choice: quartz countertops colors, in fact, are numerous and this allow to adapt to every context and materials. White quartz countertops and black quartz countertops are only few of the chromatic possibilities. Quartz kitchen countertops have lots of pros. Among all, the non-porous surface of quartz doesn’t need sealing or special care; moreover, quartz countertops are incredibly durable and they suffer little from scratching or chipping. Further information about quartz countertops (also in terms of quartz vs marble) can be found in the blog.

Quartz watch

Quartz is used in some types of quartz watches that take advantage of its piezoelectric properties. The energy of the clock battery passes through a small quartz crystal that oscillates at a frequency of 32,768 Hz and marks the time. For this reason, a quartz watch is much more accurate than a mechanical watch.

Quartz paint

Quartz is also used to make paints to be applied to both internal and external walls. This particular type of paint is made up of water, synthetic resins and crystals quartz microgranules. The main advantages of quartz paint are that it is very simple to apply and spread, prevents the formation of algae and mold, is resistant to UV rays and abrasion and is very easy to find.

As for prices, a 14-liter can start from € 20 upwards, but on the market, they are also available in a cheaper version in the form of acrylic quartz paint, but also more expensive, from € 100 upwards for the more particular ones.

Quartz sands in the construction field

Quartz sand is widely used in the construction field. It is a sand composed of crushed, dried and sieved quartz rock and other elements such as carbonates, iron oxides, feldspar and clayey matter. From yellow to dark red in color, quartz sands contain up to 99% silica. Its use in the construction field is very varied: it is used for the purification of drinking water, for sandblasting and abrasives, for flooring and wall coverings, for sanitary ware and much more.

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