Lulzacite

Lulzacite is a strontium-containing phosphate mineral with the chemical formula Sr₂Fe²⁺(Fe²⁺,Mg)₂Al₄(PO₄)₄(OH)₁₀.^[2][3]

Lulzacite
Lulzacite found in France
General
Category	Phosphate minerals
Formula	Sr2Fe2+(Fe2+,Mg)2Al4(PO4)4(OH)10
IMA symbol	Lul[1]
Strunz classification	8.BK.25
Crystal system	Triclinic
Crystal class	Pinacoidal (1) (same H-M symbol)
Space group	P1
Identification
Color	Grayish-green to yellowish-green
Crystal habit	Anhedral aggregates; rarely small euhedral crystals
Cleavage	None
Mohs scale hardness	5.5–6
Luster	Vitreous
Diaphaneity	Transparent–translucent
Specific gravity	3.55
Optical properties	Biaxial (−)
Refractive index	nα = 1.654 nβ = 1.674 nγ = 1.684
Birefringence	δ = 0.030
References	[2][3][4]

The mineral was first described in 2000 from quartzite deposits (47°42′50″N 1°29′20″W) at Saint-Aubin-des-Châteaux, Loire-Atlantique, France, and is named after Y. Lulzac, a French geologist who discovered the mineral. In this deposit, lulzacite occurs within quartz and siderite veinlets at quartzite–limestone contacts. Other minerals found in the veinlets include apatite, goyazite, and pyrite.^[4]

Lulzacite crystallizes in the triclinic system with P1 space group. It is isostructural with jamesite (Pb₂Zn(Fe²⁺,Zn)₂Fe³⁺₄(AsO₄)₄(OH)₁₀).^[4][5]