Haggertyite

Haggertyite is a rare barium, iron, magnesium, titanate mineral: Ba(Fe²⁺₆Ti₅Mg)O₁₉ first described in 1996 from the Crater of Diamonds State Park near Murfreesboro in Pike County, Arkansas. The microscopic metallic mineral crystallizes in the hexagonal system and forms tiny hexagonal plates associated with richterite and serpentinitized olivine of mafic xenoliths in the lamproite host rock. It is an iron(II) rich member of the magnetoplumbite group. It is a light grey opaque mineral with calculated Mohs hardness of 5.

Haggertyite
General
Category	Oxide mineral
Formula	Ba(Fe2+6Ti5Mg)O19
IMA symbol	Hgt[1]
Strunz classification	4.CC.45
Crystal system	Hexagonal
Crystal class	Dihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m)
Space group	P63/mmc
Unit cell	a = 5.926, c = 23.32 [Å]; Z = 2
Identification
Color	Gray
Crystal habit	Microscopic hexagonal platelets
Mohs scale hardness	5
Luster	Metallic
Diaphaneity	Opaque
Specific gravity	4.87 (calculated)
References	[2][3]

It was named for geophysicist Stephen E. Haggerty (born 1938) of the Florida International University.