Prase Quartz: Properties, Uses, Occurrence

Prase quartz is a macrocrystalline variety of quartz with a distinctive green color. Unlike other quartz varieties, its beauty doesn't come from internal fractures or rainbows of light, but from a secret hidden within its very structure: microscopic inclusions of green minerals.

Prase quartz, sometimes simply called prase, is a captivating variety of the mineral quartz characterized by its verdant hue. Its name derives from the Greek word "prason," meaning "leek," alluding to its resemblance to the leafy green vegetable.

The verdant charm of prase quartz arises not from its own structure but from microscopic inclusions of green minerals like actinolite (amphibole) and hedenbergite (pyroxene). These inclusions act like tiny filters, scattering blue and yellow wavelengths of light and allowing only green to pass through, resulting in the gemstone's unique color. The intensity and hue of the green can vary from pale, almost milky, to a deep, vibrant emerald, depending on the type and concentration of inclusions.

Prase quartz is not a separate mineral from quartz, but rather a variety of quartz colored by green inclusions.

How Prase Quartz is Formed

The green color of prase quartz originates from tiny inclusions of actinolite, an amphibole mineral, or hedenbergite, a pyroxene mineral. These microscopic inclusions scatter light within the quartz crystal, producing the characteristic verdant shade.

Prase quartz is typically found in skarns, which are rocks that form when magma of igneous rocks intruded into carbonate rocks. The hot silica-rich fluids that escape from the cooling magma enter the neighboring carbonate rocks and cause chemical alterations and the formation of new minerals.

Prase quartz is often found associated with pyroxenes, amphiboles, epidote, iron oxide minerals, and garnets.

Prase Quartz Crystal Showcasing moss-green actinolite Inclusions

Prase Quartz from Serifos Island, Greece
Photo: Anton Watzl

Prase Quartz Properties

Composition: Silicon dioxide (SiO₂) with microscopic inclusions of green minerals like actinolite (amphibole) and hedenbergite (pyroxene).

Color: Pale, almost milky green to a deep, vibrant green. The intensity and hue depend on the type and concentration of inclusions.

Luster: Vitreous (glassy), reflecting light like glass does.

Crystal System: Trigonal, with hexagonal symmetry in crystal form.

Streak: White, the same color as the powdered form.

Hardness: 7 on the Mohs scale, meaning it can scratch most other minerals except for harder ones like topaz and diamond.

Cleavage: None, meaning it doesn't break along predictable planes.

Crystal Form: Can occur in well-defined, hexagonal prismatic crystals with pyramidal terminations, but more commonly found in massive, botryoidal (grape-like) or stalactitic forms.

Density: 2.6 - 2.65 g/cm³, slightly less dense than clear quartz due to the lighter green minerals within.

Transparency: Translucent to nearly opaque, depending on the concentration and distribution of inclusions. Denser stones tend to be less transparent.

Fracture: Conchoidal, meaning it breaks with smooth, curved surfaces like a seashell.

Specific Gravity: 2.6 - 2.65, slightly less than clear quartz due to the lower density of green inclusions.

Solubility: Insoluble in water and common acids.

Magnetism: Non-magnetic.

Fluorescence: Weak, some prase quartz may show a faint green glow under ultraviolet light.

Pleochroism: Weak, some stones may exhibit a slightly darker green hue in one direction of light.

Refractive Index: 1.544 - 1.553, slightly lower than clear quartz due to the different composition of the green inclusions.

Inclusions: Microscopic green minerals like actinolite and hedenbergite are responsible for the characteristic green color. These inclusions scatter blue and yellow wavelengths of light, leaving only green to pass through, creating the vibrant color.

Varieties of Prase Quartz

Prase quartz exhibits a range of green tones, from pale and delicate to deep and rich. Its transparency varies from translucent to opaque, depending on the concentration of inclusions. The gemstone often occurs in massive, granular forms, but well-formed crystals are also found. Prase quartz is often distinguished from chrysoprase, another green quartz variety, by its coarser grain size and more opaque appearance. Prase quartz can vary in color from pale green to deep green, and can sometimes exhibit a mossy appearance.

Natural roght Prase Quartz crystals on matrix from Serifos, Greece.
Photo: TheMineralCollective

Prase Quartz Distribution and Localities

Prase Quartz, a green variety of quartz, can be found in various locations around the world. The green color is typically caused by inclusions of minerals such as actinolite or chlorite. Here are some notable localities where Prase Quartz has been found:

Europe:

Elbe River valley, Germany: Historically mined for centuries, this region offers some of the finest quality prase quartz.

Swiss Alps: Pockets of prase quartz can be found in the mountains, particularly in Ticino and Valais cantons.

French Alps: Known for its beautiful green-blue prase quartz, particularly in the Rhône-Alpes region.

Asia:

Ural Mountains, Russia: Deposits of prase quartz are found throughout the mountain range.

Himalayas, India and Nepal: Pockets of prase quartz can be found in the higher reaches of the Himalayas.

Hokkaido, Japan: Prase quartz can be found in the metamorphic rocks of this island.

Africa:

Madagascar: Renowned for its high-quality prase quartz, often with a vibrant green color.

Namibia: Deposits of prase quartz are found in the country's metamorphic rocks.

South Africa: Pockets of prase quartz can be found in the country's various geological formations.

North America:

California, USA: Deposits of prase quartz are found in the Sierra Nevada Mountains and Coast Ranges.

Oregon, USA: Pockets of prase quartz can be found in the state's metamorphic rocks.

Vermont, USA: Greenstone formations in the state sometimes contain prase quartz.

South America:

Minas Gerais, Brazil: This region is known for its high-quality prase quartz, often with a deep green color.

Colombia: Deposits of prase quartz are found in the country's metamorphic rocks.

Peru: Pockets of prase quartz can be found in the Andes Mountains.

Prase Green Quartz Necklace Raw Crystal Pendant

Prase Green Quartz Necklace Pendant

Uses of Prase

Prase, a green variety of quartz, is primarily valued for its aesthetic qualities, and it is commonly used in the production of ornamental and lapidary items. Here are some common uses and applications of Prase:

Jewelry:

Prase Quartz, with its beautiful green color, is often used in jewelry design. It can be cut into cabochons, beads, or faceted gemstones for use in rings, earrings, necklaces, and other decorative pieces.

Ornamental Items:

Prase is frequently used to create ornamental items such as carvings, sculptures, and decorative objects. Its attractive green hue adds a touch of natural beauty to various artistic creations.

Collectibles:

Mineral and crystal enthusiasts often collect Prase specimens for their unique color and interesting crystal formations. Prase Quartz specimens can be displayed in collections or used in educational settings to study mineralogy.

Metaphysical and Spiritual Practices:

In some belief systems and alternative practices, certain minerals and crystals, including Prase, are believed to possess metaphysical properties. Prase Quartz may be used in meditation, energy work, or as part of crystal healing practices.

Lapidary Arts:

Prase, like other varieties of quartz, can be shaped and polished by lapidaries to create various objects. Lapidary artists may use Prase to make cabochons, beads, and other polished items for use in jewelry and crafts.

Prase Quartz Metaphysical Properties

Prase quartz is believed to possess various beneficial properties, including promoting growth, creativity, and inner peace. It is also associated with healing and balance, making it a popular choice for crystal healing practices. Prase quartz is often incorporated into jewelry, crafted into cabochons, beads, and carvings. Its vibrant green color adds a touch of elegance and sophistication to any piece.

Conclusion

Prase quartz is a mesmerizing variety of quartz with a unique story and captivating beauty. Its vibrant green color, durability, and potential for metaphysical uses make it a sought-after gem for various purposes.