Faced with the dazzling array of quartz crystal products in the market, many American crystal retailers find themselves puzzled: How many varieties do quartz crystal types actually include? How should quartz crystal types be scientifically classified? From transparent clear quartz to mysterious smoky quartz, from gentle rose quartz to brilliant amethyst, each type of quartz crystal has its unique market positioning and customer base.
Classification by Color
1. Clear Quartz
Clear quartz, also known as colorless crystal, is a colorless and transparent single-crystal quartz and the most common crystal variety found in the market.
Regular clear quartz has relatively low value, with high purity specimens being preferred. However, when it contains other inclusions, both its appearance and value undergo significant changes. (For detailed varieties, see the section "Classification by Inclusions" below)
2. Citrine
Citrine commonly appears in light yellow, yellow, golden yellow, brownish yellow, and orange-yellow colors.
The color formation may be related to paired iron elements occupying positions within the crystal structure.
Natural citrine occurs rarely in nature and is commonly found associated with amethyst and crystal clusters. Most vividly colored citrine available in the market is either heat-treated amethyst or synthetic citrine.
3. Rose Quartz
Rose quartz can display colors ranging from pinkish white, light pink to pink and pinkish purple. The coloration is caused by trace amounts of Mn (manganese) and Ti (titanium) in its composition.
In some cases, rose quartz may contain fine needle-like rutile inclusions arranged in parallel, which can display asterism when cut into cabochons or spheres.
The color of rose quartz is somewhat unstable - it will fade when heated, and prolonged exposure to sunlight will also cause the color to lighten.
4. Amethyst
Amethyst is transparent to semi-transparent purple quartz crystal.
Amethyst varies in color saturation from deep to light. High-quality amethyst has the most jewelry-like appearance among crystals and is one of the most popular varieties in the American crystal wholesale market.
Amethyst contains trace amounts of iron, which is the key factor in amethyst's color formation.
However, it's important to note that: under heating or prolonged sun exposure, the color centers in amethyst will be damaged, causing fading.
5. Smoky Quartz
Smoky quartz, also known as smoky crystal, refers to transparent quartz with smoky, tea-colored, or brown hues.
6. Ametrine
Ametrine is a type of quartz crystal where purple and yellow colors coexist within the same crystal. Purple and yellow each occupy different sections of the crystal, with a clear boundary at the junction between the two colors.
Research suggests that the bicolor nature of natural ametrine is caused by twinning. Most of the inexpensive, large-volume ametrine popular in the market is produced by heat-treating amethyst with half of it covered.
7. Green Quartz (Prasiolite)
Green quartz displays elegant pale green to yellow-green hues and is a relatively rare variety of quartz. Its captivating green color is primarily caused by ferrous iron ions (Fe²⁺) within the crystal structure. Natural green quartz is extremely rare, with most market specimens being heat-treated or irradiated amethyst.
Classification by Inclusions
1. Phantom quartz
also known as garden quartz, is clear quartz that has encapsulated clay, sediment, and other minerals during its growth process. After cutting and polishing, those specimens that display special scenic patterns are called inclusion quartz or phantom crystals.
Phantom quartz varieties differ based on the color of their inclusions. The most valuable type is "Green Phantom" crystal, which contains chlorite inclusions.
When the color of volcanic sediment inclusions changes, there are also other color varieties such as White Phantom, Red Phantom, Pink Phantom, Yellow Phantom, and Purple Phantom. Besides Green Phantom, "Four Seasons Phantom" crystals that contain white, yellow, green, and red phantom inclusions within the same specimen also have high value.
2. Rutilated Quartz
Rutilated quartz is formed by needle-like and fibrous inclusions of rutile, tourmaline, actinolite, and other minerals.
Within colorless transparent quartz, there exist needle-like, hair-like, or fibrous mineral inclusions.
The "hair" in rutilated quartz comes in various colors including gold, red, green, black, and silver. The market categorizes rutilated quartz varieties based on color: Golden Rutilated Quartz, Red Copper Rutilated Quartz, Black Rutilated Quartz, Green Rutilated Quartz, and so on.
Classifying rutilated quartz by color is relatively simple and easy to understand, but this naming convention tends to follow market habits. A more professional classification method should be based on the mineral composition of the included "hair."
Rutile Quartz: The hair consists of rutile, commonly distributed in bundled or radiating patterns, appearing in golden yellow, light yellow, brownish yellow, and other colors.
Actinolite Quartz: The hair is green to dark green in color (under 10x magnification, the hair appears as flat, elongated plates, which distinguishes it from tourmaline rutilated quartz).
Tourmaline Quartz: Commonly appears in black and green colors. The hair consists of tourmaline (characteristic feature: under magnification, the cross-section of the hair shows a curved triangular shape), and is relatively common in the market.
Limonite Quartz: The hair appears in red and reddish-brown colors.
Blue Rutilated Quartz: The hair consists of natural dumortierite inclusions, displaying a dreamy blue color. However, most dumortierite hair inclusions are not particularly long. There are also dyed blue rutilated quartz specimens in the market, so careful distinction is needed.
3. Titanium Quartz
When the needle-like minerals in rutilated quartz become densely packed into plate-like formations, it is called "Titanium Quartz." Titanium quartz has higher value than regular rutilated quartz.
4. Rabbit Hair Quartz
When the needle-like, hair-like, or fibrous mineral inclusions in quartz are extremely fine and dense, appearing as delicate hair strands softly intertwined, they resemble the soft fur of animals.
Based on the different mineral compositions of the inclusions, rabbit hair quartz comes in various colors including white rabbit hair, green rabbit hair, red rabbit hair, yellow rabbit hair, and gray rabbit hair.
5. Fire Quartz/ Golden Hematoid Quartz
Fire quartz commonly appears in brown, reddish-brown, brownish-yellow, and yellow colors. The varieties are generally classified as Yellow Fire Quartz(Golden Hematoid Quartz) and Red Fire Quartz. Due to the diverse distribution patterns of colors in fire quartz, it often displays wonderful patterns and scenic formations.
6. Strawberry Quartz
When clear quartz contains dense flaky, fine needle-like, and sometimes "beetle leg"-shaped inclusions of iron oxide minerals such as hematite and goethite, displaying elegant pink, brownish-red, and bright red colors, it is called strawberry quartz.
7. Rainbow Quartz
Some quartz crystals with well-developed fractures can display vivid rainbow colors, forming rainbow quartz.
Due to tiny air bubbles inside or liquid filling the fractures within the crystal, when light strikes the bubbles and liquid in the fractures, interference occurs and produces rainbow colors.
8. Enhydro Quartz
Quartz crystals that contain liquid inclusions within their transparent structure are called "Enhydro Quartz."
The formation of enhydro quartz originates from the crystal capturing diagenetic and ore-forming solutions during its growth process, commonly found in magmatic hydrothermal deposits. According to the state of the enhydro, enhydro quartz can be classified into: liquid-phase enhydro quartz (containing pure liquid internally), gas-liquid two-phase enhydro quartz (containing both gas and liquid within the enhydro), and liquid-solid two-phase enhydro quartz (containing liquid and solid inclusions within the enhydro).
Petroleum Enhydro Quartz For quartz crystals where the internal liquid inclusions appear as yellow oil droplets and the solid inclusions appear as small black fragments, we call them petroleum enhydro quartz. Pakistan is a well-known source for petroleum enhydro quartz, but actually the origins of petroleum enhydro quartz are not limited to this location - it's just that dealers commonly use Pakistan as a reference point in their introductions. In terms of value, petroleum enhydro quartz has higher value than regular enhydro quartz.
9. Crystal-in-Crystal
When one crystal penetrates through or completely encapsulates another crystal within it, we call this unique phenomenon "Crystal-in-Crystal."
Solid inclusions in quartz can also contain garnet, fluorite, pyrite, solid bitumen, and other minerals. Due to the different inclusions, the internal landscapes of crystals vary accordingly. Some rare crystal-in-crystal specimens also hold considerable collectible value in the market.
Through the detailed classification introduction above, we can see that the diversity of quartz crystal types far exceeds imagination. From basic color classifications to complex inclusion categorizations, each type of quartz crystal carries unique geological stories and market value. For American crystal wholesalers, mastering this scientific classification system is not only a demonstration of professional competence, but also an important foundation for developing precise procurement strategies and product positioning.