Alvite

Alvite is an obsolete mineral name that was historically applied to a variety of albite (NaAlSi₃O₈), the sodium-rich endmember of the plagioclase feldspar series. It is not recognized today as a distinct species by the International Mineralogical Association (IMA).

🌍 Origins and Naming

• Name Origin: “Alvite” was used in older mineralogical literature as a synonym or varietal name for albite.
• Status: Discredited; modern classification treats it simply as albite, a valid feldspar species.
• Historical Context: Names like alvite arose in the 19th century when regional or compositional varieties of feldspars were often given separate names before structural and chemical analysis clarified their identity.

🔬 Chemical and Structural Properties (Albite)

• Formula: NaAlSi₃O₈
• Mineral Group: Feldspar, plagioclase series.
• Crystal System: Triclinic.
• Color: White, gray, bluish, greenish, or reddish depending on impurities.
• Habit: Tabular crystals, granular aggregates, massive cleavable forms.
• Hardness: 6–6.5 on Mohs scale.
• Specific Gravity: ~2.6–2.65.
• Cleavage: Perfect on {001}, very good on {010}.
• Luster: Vitreous, pearly on cleavage surfaces.

⚙️ Geological Occurrence

• Environment: Albite occurs in granites, pegmatites, felsic igneous rocks, and low-grade metamorphic rocks.
• Associated Minerals: Quartz, microcline, muscovite, tourmaline.
• Localities: Worldwide — classic occurrences in Sweden, France, USA, and many pegmatite districts.

📖 Scientific and Collector Significance

• Petrology: Albite is a major rock-forming mineral, important in classifying igneous and metamorphic rocks.
• Collectors: Crystals can be attractive, especially cleavelandite (a platy variety of albite).
• Industrial Uses: Feldspar minerals, including albite, are used in ceramics, glassmaking, and as fillers.

✨ Conclusion

Alvite is an obsolete synonym for albite, the sodium-rich feldspar. While the name is no longer valid, it reflects the historical tendency to assign local or compositional variants separate names before mineral classification was standardized.

In short: Alvite = old name for albite (NaAlSi₃O₈), a common feldspar, now discredited as a separate species.