Important Facts About Quartz Gemstone
Quartz is the most common mineral on earth, making up about 12% of the Earth’s crust. Second only to feldspar, which is more common. However, one shouldn’t judge from this that quartz is uninteresting. In fact, the quartz family is surprisingly very diverse. The fact that they are inexpensive just means there are more opportunities for collectors. All quartz is made of silicon dioxide, but this was not discovered until the early 19th century. Prior to that, various forms of quartz were thought to be distinct minerals. This is not actually surprising, since there are two different branches of the quartz family. Macrocrystalline Quartz: When most people think of Quartz, they think of what is known as macrocrystalline quartz, which includes stone like: rock crystal, amethyst, aventurine, citrine, smoky quartz, rose quartz, blue quartz, hawk’s eye, Prasiolite, quartz cat’s eye, and tiger’s eye. Macrocrystalline quartz, as the name suggests, has large crystals with distinct shapes that can be distinguished by the naked eye, that run the gamut from tiny druzies all the way up to crystals larger. These types of quartz are mainly transparent to translucent, with a vitreous luster. Microcrystalline Or Cryptocrystalline Quartz: The other type of quartz is known as microcrystalline quartz. It has microscopically small crystals that are so minuscule and packed so tightly together that they’re completely indistinguishable to the naked eye. This type of quartz is usually translucent to opaque, with a waxy to dull or greasy luster. This kind of quartz is further divided into two subcategories, fibrous and granular. The fibrous varieties of quartz are known as chalcedony, but this name covers a remarkable array of stones. In fact, the name chalcedony refers to solid colored microcrystalline quartz, especially of a light color. The patterned varieties of quartz tend to have their own names. The most prominent of these include agate, distinguished by its bands of color; onyx, which is black and white layered chalcedony; chrysoprase, an apple-green variety of chalcedony, colored by nickel. and carnelian, a yellow-orange to a reddish-orange variety that is colored by iron The granular varieties include jasper and bloodstone. Jasper is typically multicolored, spotted, or flamed. Especially valuable pieces form patterns that look like natural landscapes. While Bloodstone, also known as heliotrope, is dark-green with flecks of red, caused by iron oxide. The diversity of these quartz varieties is remarkable. For example, Agate has more than a dozen different types, many of them much sought after by collectors. They have unusual names like eye agate, which forms ring shapes with a point in the center; moss agate, distinguished by its moss-like patterns; and fire agate, which displays an unusual iridescence. Different Types of Treatment or Enhancement Used: All Quartz Gemstones types receive different types of treatment or enhancements; there are very few varieties of quartz that are not treated. A few varieties of quartz that are not colorless and natural are Latte Quartz, Champagne Quartz. Colorless quartz is always untreated. Colored stones can occasionally be enhanced in color by dying (a combination of bathing in color agent solutions, followed by heating), irradiation (bombardment with low-level radioactivity), or heating. Reliable gemstone dealers will always inform their customers about any kind of treatment. Some quartz gems can lose their color saturation over a period of time in daylight. The original color can be restored by X-ray radiation. Amethyst: Normally untreated, but they may have a treatment of heat of 878-1382 °F which results in light yellow, red-brown, green, or colorless varieties. Some amethysts can lose their color saturation in daylight. The original color can be restored by X-ray radiation. Ametrine: No known treatments, but there are synthetic versions available. Aventure: Aventurine is a type of Quartz typically used for carvings and cabochons. They are mainly dark green sometimes with a glittery metallic appearance caused by included green mica. Large deposits of aventurine are found in Brazil, India, Austria, Russia, and Tanzania. They are not known to be enhanced. Bi-colored Quartz: Quartz crystals of different colors often form together to form interesting bi-colored stones. These can be part of natural citrine and smokey quartz, or amethyst and colorless quartz, these gemstones are beautiful. Another form of bi-colored quartz is Ametrine which is Amethyst & Citrine. Bi-colored Quartz is a natural mineral in nature and not enhanced, This gemstone can be created synthetically or treated by dying/irradiation/heat to create mass quantities or colors not typically found in nature. When natural bi-colored quartz is found in nature, there is no need for treatment or enhancement. Carnelian: Many carnelians being offered in the gemstone market today are actually Agates that have been treated (dyed and then heated). There are many ways to identify natural carnelian. When held against the light, the dyed agate will display striping, while the natural carnelian will show a cloudy distribution of color. Natural carnelian is increasingly rare. Carnelian can be Heated to darken the color. Multiple Types of Chalcedony: Chalcedony, mean any translucent, microcrystalline quartz with a single color, whether it has a unique variety name or not. Its colors are bluish, white, or grey. The various types differ in color due to metallic impurities, such as iron, nickel, copper, and titanium, present during crystallization. Agate: It is distinguished by having multiple colors. The banded agates are some of the most popular agates. A rarity is the so-called fire agate. The iridescent colors of red, gold, green, and rarely, blue-violet, result from interference between light rays traveling through these thin layers. Agate jasper, which grows with agate, is green, brown, or yellow blended. Onyx is a layered gemstone with a black base and a white upper layer. Agate is usually dyed with bright colors. Bloodstone: Is an opaque, dark-green chalcedony with red spots. Bloodstone is not treated in any way. Blue Chalcedony: Also called “Mohave” and “Mt. Airy Blues”, originating in California and Nevada, are slightly to moderately greyish blue with a light to medium color range. Blue chalcedony from Namibia, often known as “African Blue”, varies from greyish to nearly pure blue and from light to medium-dark. The most unusual and valuable type is from Oregon. Its blues are actually modified by slight to moderate amounts of pink, making a noticeably lavender gemstone, which nonetheless is called “Holly Blue.” Misty blue Chalcedony is not treated. The Aqua blue chalcedony is dyed. Chalcedony: In the narrow sense, comes in bluish-white or grey. Uni-colored chalcedony sometimes is called Onyx: Black and colored onyx is dyed. Carnelian ranges in colour from yellow-orange to rich, near reddish-orange, to orangey-brown, and varies from semi-opaque to highly translucent. Chrysoprase: Apple green chalcedony that derives its color from nickel, ranges from nearly opaque to nearly transparent. Its color spectrum includes Olive, to nearly pure greens of medium tone. Very fine and highly saturated pieces have been successfully misrepresented as Imperial jade. Chrysoprase is not enhanced. Chrysocolla Chalcedony: Marketed as “Gem Silica” this relatively rare, blue to blue-green, opaque to near-transparent material is the most expensive type of chalcedony. Its color agent is copper. Cat’s Eye Quartz: Comes in a variety of colors: Yellow, brown, green, grey, and white. Cat’s Eye Quartz: This is a reflection of light by parallel fibers, needles, or channels, which resembles the slit eye of a cat. When the gemstone is rotated, the cat’s eye glides over the surface). Inclusion causes many gemstones to lose value, but without inclusion, we would not see the beauty of the Cat’s eye in these gemstones. Treatments of Cat’s Eye Quartz: None Citrine: With the exception of natural stones, are heat-treated amethysts or smoky quartz. The used temperature defines the color. Brazilian amethyst turns light yellow at 878 °F and dark-yellow to red-brown at 1022-1040 °F. Some smoky quartz’s turn into Citrine color already at about 390 °F. Crackle Quartz: This type of quartz can appear in any color dyed or seen in many colors, pink, yellow, blue and green, and more. The quartz is Heated and cooled in a dye bath, where it is then sold in the chip, tumbled, or even faceted form and gives a cracked appearance. Often many times, lower graded quartz can be used if using for chips or tumble beads. Enhancement: Heat, dye. Dendritic Quartz: Are quartz with fossilized plant life, really an agate or chalcedony, Natural Untreated Quartz Druzy Quartz: Found in the interiors of quartz geodes, when first found, natural geodes look like solid, round rocks. Most of these are actually solid, with only 5% or so being hollow with crystals forming on the inside. While only a fraction of these will have formed with the fine unblemished that create the unforgettable Drusy sparkle. However, the majority of stones are unattractive off-white or a washed-out grey. Only a few provide the finest shades of gem-quality Drusy quartz. Treatments: Typically, the quartz crystals are dyed. Grey Quartz: Bluish Grey, the color coming from a fibrous material included in the Quartz, this gemstone is not known to be Enhanced or Treated in any way. Lemon Quartz: This is one of the most common in the quartz crystalline family; treated with irradiation and heat. Lepidocrocite: The color of Lepidocrocite ranges from a dark yellow to a dark red. Lepidocrocite crystals may often be tarnished with iridescent colors, making them appear very similar to Hematite mineral. Often called strawberry quartz when seen in a clear state and red or pinkish-red spotting. This quartz is found in meteorites. This quartz is not treated or enhanced in any way. © Crystal Classics Medusa Quartz: Not known to be treated. Milk Quartz: The white color may be caused by minute fluid inclusions of gas or liquid trapped inside the quartz crystal during the crystal formation. The cloudiness caused by the inclusions effectively increases its use in most optical and quality gemstone creations like carvings, also known as Phantom quartz. Milk quartz also has been known to have gold inclusion. Not known to be treated or enhanced. Prasiolite (Green Amethyst): Prasiolite is not found in nature. Heat-treated violet amethyst or yellowish quartz turns into leek-green Prasiolite. WARNING: Whenever dark green amethyst is offered (forest green & other darker colors); chances are they are Synthetic Quartz or Dyed Quartz. Rose Quartz: No known treatments. Rutile Quartz: While most varieties of transparent quartz are valued more when they show no inclusions, but rutilated quartz is valued specifically for the lovely patterns formed by the delicate golden needles of rutile inside quartz crystal. There is currently, no do commented treatment is used to add this lovely inclusion. Smokey Quartz: Coloured stones can occasionally be enhanced in color by dying, irradiation, or heating. Reliable gemstone dealers will always inform their customers about any kind of treatment. Some quartz gemstones can lose their color saturation over a period of time in daylight. The original color can be restored by X-ray radiation. Star Quartz: This variety of quartz will display a six-rayed star effect if cut en cabochon and showed against a dark background. These gemstones are often painted black on the back, or assembled with black onyx as a doublet to display the star effect better. The quartz itself is not treated. Tiger’s Eye Quartz: Gold-yellow, gold-brown (similar to hawk’s eye effect, the ray of light is brown colored due to oxidized iron inclusions); they are not enhanced. Hawk’s Eye Quartz: Blue-gray to blue-green (small ray of light on the surface that resembles the eye of a bird of prey) also called Crocidolite. Hawk’s eye is not enhanced. In today’s gemstone market quartz is being used to fraudulently stand-in for many other gemstones such as Topaz, Ametrine, and many other natural gemstones, we see this the case with many types of topaz such as Mystic topaz and other bi-color or multi-color gemstones with the treatment of chemicals. This is extremely unfortunate, but as vendors, we need to know what to look for when providing gemstones for our customers, one way to prevent buying synthetic gemstones is to use a reliable source for the main gemstones you buy, for your own collection, or for resale purpose. Asia has been a regular source of synthetic gemstones for over 20 years. The market is flooded with these synthetic or fake gemstones. The scarcity of natural resources or gemstones is one of the main reasons this has happened. Also, dangerous mining conditions and Laws preventing importing or mining gemstones are all issues that cause the creation of synthetic gemstones, and there is a market for the item.
