Mazzite-Na

Chemical formula: Na₈(Si₂₈Al₈)O₇₂·₃₀H₂O

A rare zeolite with a complex structure, forming acicular crystals in volcanic vesicles.

## Characteristics Mazzite-Na is a hydrated sodium, potassium, and magnesium aluminosilicate, belonging to the zeolite group. This mineral forms characteristic, fine, acicular or fibrous crystals, which often arrange themselves into radial or spherulitic aggregates. Individual crystals are typically colorless and vitreous transparent, but in aggregates, they appear white or creamy. ## Physical Properties Mazzite-Na crystals exhibit a hardness of approximately 4-5 on the Mohs scale. They have a vitreous luster. They are transparent when occurring as single crystals, and translucent to opaque in aggregate form. The mineral's density is about 2.11 g/cm³. ## Colors and Varieties This mineral is typically colorless or white. No colored varieties or trade names are distinguished. ## History and Name The name "mazzite" was given in honor of Professor Fiorenzo Mazzi (1924-2012), an Italian mineralogist from the University of Pavia, for his contributions to zeolite research. The suffix "-Na" refers to the dominant sodium in its chemical composition. The mineral was first described in 1974 by G. Gottardi and E. Passaglia based on material from Mont Semiol, Châtelneuf, France. ## Uses Due to its rarity and small crystal size, mazzite-Na has no industrial applications. It is solely an object of interest for collectors specializing in rare minerals and zeolites.

Properties

Mohs hardness: 4-5
Luster: Vitreous
Streak: White
Density: 2.11
Cleavage: None
Fracture: Uneven
Transparency: Transparent to translucent
Crystal system: Hexagonal

Diagnostic features

## Identification A characteristic feature of mazzite-Na is its fine, acicular crystals gathered in radial or spherical aggregates. It occurs in vesicles and fissures of volcanic rocks. Identification most often requires advanced analytical methods, such as X-ray diffraction (XRD) or chemical analysis (EDS). ## Distinguishing from Similar Minerals Mazzite-Na can be confused with other zeolites with acicular or fibrous habits, such as natrolite, mesolite, scolecite, or thomsonite. Distinguishing them based on visual characteristics is practically impossible and requires specialized laboratory tests. However, mazzite-Na is significantly rarer than the aforementioned minerals. ## Crystal Forms It forms hexagonal, prismatic, acicular crystals, elongated along the [0001] axis. These crystals almost always occur as radial, spherulitic, or fibrous aggregates.

Geological environment

## Genesis Mazzite-Na is a hydrothermal mineral. It forms at low temperatures in gas vesicles and fissures within altered volcanic rocks, such as basalts and tuffs. ## Mineral Associations It co-occurs with other zeolites, such as phillipsite, chabazite, willhendersonite, gismondine, as well as with calcite and opal. ## Localities The most important occurrences of this mineral include the type locality at Mont Semiol near Châtelneuf in Auvergne (France). It is also known from the Höwenegg quarry in Hegau (Germany) and from several localities in the Czech Republic (near Ústí nad Labem).

Rarity

Very rare

For collectors

## Quality Criteria The most valued specimens by collectors are those with well-formed, rich aggregates of acicular crystals, forming aesthetic "hedgehog" or "ball" formations on a contrasting rock matrix. The absence of damage to the delicate needles is important. Due to the small size of the crystals, specimens are usually "micromount" or miniature type. ## Popular Localities Specimens from the classic locality at Mont Semiol in France and from Höwenegg in Germany are considered the best.

Care and storage

## Cleaning Specimens should be cleaned exclusively with cold, distilled water, using a very soft brush to remove dust. Ultrasonic cleaners should be avoided, as they can damage delicate crystals. ## What to Avoid Contact with acids and other chemicals should be avoided. As a zeolite, mazzite-Na is sensitive to heating, which can lead to irreversible loss of water from the crystal structure and destruction of the specimen. It should also not be soaked for extended periods. ## Storage Mazzite-Na specimens are very fragile and susceptible to mechanical damage. It is best to store them in closed "micromount" boxes, away from dust and vibrations. They should be protected from direct sunlight and high temperatures.

Sources

IMA Mineral List (CNMNC)