Scorzalite
Chemical formula: Fe<sup>2+</sup>Al<sub>2</sub>(PO<sub>4</sub>)<sub>2</sub>(OH)<sub>2</sub>
Scorzalite is a rare, blue-green mineral from the lazulite group, valued by collectors for its intense color and well-formed crystals.
Properties
- Mohs hardness
- 5.5-6
- Luster
- Vitreous
- Streak
- White
- Density
- 3.4
- Cleavage
- Indistinct on {100}
- Fracture
- Uneven, Sub-Conchoidal
- Transparency
- Translucent to transparent
- Crystal system
- Monoclinic
Diagnostic features
## Identification Key diagnostic features of scorzalite are its intense, dark blue to blue-green color, vitreous luster, and relatively high hardness (5.5-6). It occurs in characteristic geological environments, such as phosphate-rich granitic pegmatites or high-grade metamorphic rocks. ## Distinguishing from Similar Minerals Scorzalite is most often confused with lazulite. Distinguishing these two minerals based on visual characteristics is practically impossible without advanced chemical analysis (determining the Fe/Mg ratio). Lazulite is typically lighter and more purely blue, while scorzalite tends to have darker, more greenish or grayish hues. It can also be confused with azurite, which is, however, much softer (hardness 3.5-4) and reacts with hydrochloric acid. ## Crystal Forms Scorzalite crystals are monoclinic and typically occur as short, thick prisms or wedge-shaped forms. They often form granular aggregates or massive masses, in which individual crystals are difficult to distinguish.
Geological environment
## Genesis Scorzalite forms in two main types of environments. Firstly, in phosphate-rich granitic pegmatites, where it crystallizes in the late stages of hydrothermal processes. Secondly, in aluminum-rich metamorphic rocks, such as quartzites, where it forms under conditions of amphibolite to granulite facies metamorphism. ## Mineral Associations In pegmatites, scorzalite often co-occurs with minerals such as quartz, albite, muscovite, beryl, as well as other phosphates, e.g., triphylite, lithiophilite, apatite, and brazilianite. In metamorphic rocks, its typical associated minerals are quartz, andalusite, sillimanite, kyanite, and also lazulite, with which it forms a series. ## Localities The most important and classic occurrence, from which the best crystals originate, is the Córrego Frio mine in Linópolis, Minas Gerais, Brazil (type locality). It is also known from several localities in the United States, especially from the Rapid City area in South Dakota and from the Palermo mine and others in the North Groton area in New Hampshire. Occurrences have also been reported in Sweden, Rwanda, and Australia.
Rarity
Rare
For collectors
## Quality Criteria The most desirable specimens for collectors are those with well-formed, sharp crystals of intense, deep blue color. Crystals embedded in a contrasting matrix (e.g., on white quartz or albite) are highly valued. The size of the crystals, their luster, and the absence of mechanical damage also significantly increase the specimen's value. Specimens from the type locality (Minas Gerais, Brazil) are historically the most important and sought after. ## Popular Localities Collectors most appreciate specimens from Minas Gerais, Brazil, which are considered the global standard for this mineral. Good quality crystals, though usually smaller, also come from pegmatites in New Hampshire and South Dakota in the USA.
Care and storage
## Cleaning Scorzalite specimens should be cleaned very carefully. It is best to use a soft brush to remove dust. For heavier soiling, a damp soft cloth or cotton swab with distilled water can be used, immediately drying the specimen. Ultrasonic cleaners should be avoided. ## What to Avoid Avoid contact with acids and other strong chemicals that can damage the mineral's surface. Scorzalite is sensitive to rapid temperature changes. Prolonged exposure to direct sunlight may potentially cause color fading, although this is not well documented. ## Storage Specimens should be stored in stable conditions, away from heat sources and direct sunlight. To avoid scratches from harder minerals (e.g., quartz), it is best to store it in a separate box or in a display cabinet away from other specimens. It is a brittle mineral, so it should be protected from impacts and drops.