Where is Basalt with Zeolites found?

Basalt with Zeolites occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.

Where to find Basalt with Zeolites

Collecting tips

1. Look for Vesicular Basalt. Zeolites form in the gas bubbles (vesicles) of basalt. Look for dark, fine-grained rocks with visible holes or cavities. Outcrops along road cuts, stream beds, and coastal cliffs in volcanic regions are good places to search.
2. Examine Cavities Closely. Once vesicular basalt is found, inspect the cavities for crystalline growths. Zeolites often have distinct crystal forms and colors that contrast with the dark basalt.
3. Check for Hydrothermal Alteration. Areas with evidence of past hydrothermal activity (e.g., mineral staining, altered rock) are more likely to host zeolite-filled amygdales.
4. Safety Precautions. When collecting, wear appropriate safety gear including eye protection and gloves. Basalt can be sharp, and breaking rocks can produce sharp fragments. Be aware of unstable rock faces in quarries or cliffs. Some zeolites, particularly fibrous varieties like Erionite (though less common in basaltic amygdales than other zeolites), can be hazardous if inhaled, similar to asbestos. While common zeolites like Stilbite and Heulandite are generally safe, always handle specimens with care and avoid creating dust. Wash hands after handling. No specific radioactive or toxic elements are typically associated with common basaltic zeolites, but general mineral handling precautions are always advisable.

Quick Check

Color:

Dark gray to black matrix with white, pink, orange, or colorless crystals in cavities.

Luster:

Dull to sub-vitreous for basalt; vitreous to pearly for zeolites.

Streak:

Basalt: grayish-black; Zeolites: white.

Explore Basalt with Zeolites