From Grand Theft Wiki

Quartz West
Liberty City Subway station
Station information
Line	A/J Algonquin Outer Line
Service	A/J
Platforms	2
Tracks	2
Other
Borough	Algonquin
Next north	Manganese West: A/J
Next south	Vauxite: A/J

Quartz West is a station on the Liberty City Subway system. It is located at the intersection of Quartz Street and Ivy Drive South at the border between Middle Park West and Varsity Heights in northern Algonquin, Liberty City. The A/J Algonquin Outer Line stops at the station.