Mazzite-Mg

Chemical formula: Mg₅(Si₂₆Al₁₀)O₇₂·₃₀H₂O

Mazzite-Mg is a rare mineral from the zeolite group, forming tiny, hexagonal crystals with a silky luster, found in gas vesicles of volcanites.

## Characteristics Mazzite-Mg is a hydrated magnesium, potassium, and calcium aluminosilicate, belonging to the zeolite group. It forms very small, acicular or fibrous crystals with a hexagonal prismatic habit, which often arrange into radial or spherulitic aggregates. Due to the small size of the crystals, its macroscopic features are difficult to observe without magnification. ## Physical Properties This mineral has a hardness of approximately 4 on the Mohs scale. It exhibits a silky luster, and its crystals are typically translucent. The density is about 2.11 g/cm³. ## Colors and Varieties It is a colorless or white mineral. No colored or commercial varieties are distinguished. ## History and Name The name "mazzite" comes from the surname of Fiorenzo Mazzi (1924-2012), an Italian mineralogist and crystallographer from the University of Pavia, in recognition of his contributions to zeolite research. The suffix "-Mg" indicates the dominance of magnesium 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.

Properties

Mohs hardness: 4
Luster: Silky
Streak: White
Density: 2.11
Cleavage: Distinct/Good on {10-10}
Fracture: Uneven
Transparency: Translucent
Crystal system: Hexagonal

Diagnostic features

## Identification Identification of Mazzite-Mg in the field is practically impossible. It requires advanced analytical methods such as X-ray diffraction (XRD) and chemical analysis (EDS/WDS) to confirm its crystal structure and magnesium-dominant composition. Visually, it can be suspected based on its occurrence as tiny, acicular, hexagonal crystals forming radial aggregates in vesicles of volcanic rocks. ## Distinguishing from similar minerals It can be confused with many other acicular or fibrous zeolites, such as natrolite, mesolite, scolecite, or erionite. Distinguishing it from these without specialized equipment is impossible. Mazzite-Na and Mazzite-K have identical structure and appearance, with the only difference being the dominant cation, which requires chemical analysis. ## Crystal forms It forms elongated, prismatic crystals with a hexagonal cross-section, terminated by a pyramid. Most often, it occurs as radial or fibrous aggregates, as well as spherulitic clusters filling voids in the rock.

Geological environment

## Genesis It is a low-temperature hydrothermal mineral. It forms in gas vesicles and fractures in altered volcanic rocks, such as basalts and volcanic tuffs, as a result of post-magmatic solution activity. ## Mineral associations It co-occurs with other zeolite minerals, such as phillipsite, chabazite, willhendersonite, gismondine, as well as calcite and opal. ## Localities The most important localities worldwide are: - Mont Semiol near Châtelneuf (Loire, France) - type locality. - Steinbruch Höwenegg (Immendingen, Germany) - source of well-formed microcrystals. - Volcanic tuffs in the Naples region (Italy). - Bazaltovyi Mine (Rivne, Ukraine).

Rarity

Very rare

For collectors

## Quality criteria As a mineral occurring exclusively in the form of microcrystals, it is primarily valued by collectors specializing in "micromounts." The most highly rated specimens are those with well-formed, sharp crystals creating aesthetic, radial aggregates on a contrasting rock matrix. The size and richness of crystal clusters on a given specimen are also important. ## Popular localities The most sought-after specimens by collectors come from the Höwenegg quarry in Germany, known for its exceptionally well-formed microcrystals.

Care and storage

## Cleaning Specimens should only be cleaned with compressed air to remove dust. Due to extreme delicacy and potential solubility, contact with water and any chemical agents should be avoided. ## What to avoid Ultrasonic cleaning, steam cleaning, contact with acids and detergents should be avoided. The crystals are very brittle and sensitive to mechanical shocks. As a zeolite, it can undergo dehydration at high temperatures or in very dry environments, leading to its destruction. ## Storage It is recommended to store specimens in closed, stable containers (e.g., "micromount" type) to protect delicate crystals from mechanical damage, dust, and sudden changes in humidity.

Sources

IMA Mineral List (CNMNC)