Formula: Mg₂Fe³⁺(BO₃)O₂

Species:

Colour: Dark-green to black

Lustre: Silky, Sub-Metallic

Hardness: 5

Specific Gravity: 3.80

Crystal System: Orthorhombic

Member of: Ludwigite Group; Ludwigite-Vonsenite Series.

Name: Named in honor of Ernst Ludwig (1842-1915), Professor of Chemistry, University of Vienna. He worked in the areas of mineral chemistry, mineral water analysis, food chemistry and forensic chemistry. He first analyzed the material.

Type Locality: Ocna de Fier, Caraş-Severin County – Romania

The magnesium analogue of Vonsenite and Marinaite. A high-temperature mineral occurring in contact metamorphic deposits.