Where to Find Datolite in New Jersey

New Jersey datolite is a classic Triassic basalt mineral from the Watchung Mountains of Passaic, Bergen, and Essex counties. Paterson and Prospect Park quarries produced pale-green-to-yellow datolite as glassy prismatic crystals in basalt amygdules, often with prehnite, pectolite, calcite, and quartz associations. The Bergen Hill cuts (long built over) yielded the famous datolite specimens of the 19th century. Active and recently active trap-rock quarries (Great Notch, Upper Montclair, Summit) continue to surface specimens through club access. Datolite is fragile and brittle, so wrap individual crystals and avoid acid cleaning that attacks the calcium-borate composition. The most productive ground is in Paterson quarries (Passaic County), Prospect Park (Passaic County), Great Notch quarry (Essex County).

Casual hand collection of common rocks and minerals like datolite is allowed on most BLM and U.S. Forest Service land in New Jersey, with daily and annual limits set by the local field office. National parks, most state parks, and tribal land are off-limits. Always confirm rules before a trip.

Paterson quarries (Passaic County) is the standout. Other strong ground includes Prospect Park (Passaic County), Great Notch quarry (Essex County).