Herderite
Herderite is a relatively rare beryllium phosphate mineral with formula BePO4(OH,F). It crystallizes in the monoclinic system, typically forming as colorless to yellow or greenish yellow, transparent to translucent crystals. Herderite can also occur in massive or granular forms.
General Information
- Chemical Formula: BePO4(OH,F)
- Crystal System: Monoclinic
- Color: Colorless, Yellow, Greenish Yellow, Pale Blue, Pale Pink
- Streak: White
- Luster: Vitreous (glass-like) to resinous
- Diaphaneity: Transparent to translucent
- Mohs Hardness: 5 - 5.5
- Specific Gravity: 2.98 - 3.07
- Cleavage: Distinct on {010}, indistinct on {110}
- Fracture: Conchoidal to uneven
- Tenacity: Brittle
- Occurrence: Typically found in granite pegmatites, often associated with other beryllium minerals like beryl and tourmaline, and also in hydrothermal veins.
Distinguishing Characteristics
Herderite can be distinguished from similar minerals by a combination of its crystal habit, color, hardness, and associations. Its beryllium content is a key diagnostic factor, although this often requires laboratory analysis to confirm. Fluorapatite is a mineral that can be confused with Herderite.
Notable Localities
Notable localities for herderite include Brazil, the United States (Maine, New Hampshire), Russia, and various locations in Europe. Specific mines within these regions are often well-documented within mineralogical literature.
Uses
Herderite is primarily a collector's mineral due to its rarity and the aesthetic appeal of well-formed crystals. It has no significant industrial applications.
History and Etymology
Herderite was first described in 1828 by Wilhelm Karl Ritter von Haidinger. It is named in honor of Baron Sigmund August Wolfgang von Herder (1776-1838), a German mining official.