Armstrongite

Armstrongite (CaZr[Si₆O₁₅]·3H₂O)^[2] is a silicate mineral.

Armstrongite
Armstrongite found in Mongolia
General
Category	Phyllosilicate minerals
Formula	CaZr[Si6O15]·3H2O
IMA symbol	Asg[1]
Strunz classification	9.EA.35
Crystal system	Monoclinic
Identification
Color	Dark to light brown
Cleavage	Perfect on {001}, good on {100}
Tenacity	Very brittle
Mohs scale hardness	4.5
Luster	Vitreous
Streak	Brownish white
Diaphaneity	Translucent
References	[2]

Discovery and occurrence

It was first described in 1973 from an occurrence at Dorozhnyi pegmatite, Khanbogd District, Ömnögovi Province, Mongolia.^[3] It was named for the American astronaut Neil Armstrong.