Haggertyite
A rare barium-iron-magnesium titanate described in 1996 from Arkansas's Crater of Diamonds lamproite.
Intro adapted from Wikipedia (CC BY-SA).
Haggertyite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula BaFe²⁺₄Fe³⁺₂Ti₅MgO₁₉.
It crystallizes in the hexagonal crystal system (space group P6_3/mmc). It is a member of the Magnetoplumbite structural group.
Key properties: Mohs hardness 5; specific gravity 4.74; Metallic luster.
IMA symbol Hgt, IMA status: approved, named in 1996.
Occurs as isolated crystals or in small groups within the reaction rims around serpentinized mafic xenoliths in olivine lamproite (Arkansas); in the groundmass of diamondiferous olivine lamproite pipes (Australia).
It is found associated with Ti-K richterite, diopside, chrome-spinel, olivine (altered), ilmenite, jeppeite, priderite (Arkansas); Ti-phlogopite, diopside, Ti-K-richterite, olivine.
The mineral was named to honor Stephen E. Haggerty (b. 1938), Department of Geology, University of Massachusetts, USA.