Herderite

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Herderite is a rare collector gem, typically found in smaller sizes. This mineral occurs in orange, yellow green and blue colors. Herderite was first discovered in Germany in 1828, but Brazil is today's dominant source. Collectors treasure herderite for its often present twinned crystal formation and some specimens exhibit fluorescence.

Herderite Polished
Herderite Classification
Common Name Herderite
Species Herderite
Herderite Optical Properties
Transparency Transparent - Translucent
Dispersion Strength: None
Refractive Index 1.587-1.627
Birefringence 0.023-0.032
Optic Character Biaxial
Optic Sign Positive or Negative
Polariscope Reaction Aggregate (AGG), Doubly Refractive (DR)
Fluorescence SWUV: Inert to moderate yellowish white, blue or violet
LWUV: Inert to weak yellowish white
Pleochroism Unobservable
Herderite Characteristic Physical Properties
Hardness 5-5.5
Streak White
Specific Gravity 2.950-3.020
Toughness Poor
Luster Vitreous
Stability Poor
Fracture Subconchoidal
Cleavage Good, in one direction
Herderite Chemistry & Crystallography
Chemical Formula CaBePO4(F,OH)
Crystal System Monoclinic
Chemistry Classification Phosphate

Herderite Colors

  • Green Herderite Green
  • Yellow Herderite Yellow

Countries of Origin

Brazil

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Tim Matthews

Author

Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.