Victoria is world renowned for its zeolite mineral occurrences. Zeolites form in vesicles in volcanic lava rocks. They have no commercial value but form lovely crystal clusters that are valued by mineral collectors. The Victorian zeolites are found along the coast from Phillip Island to the Mornington Peninsula where thick, basaltic lava outcrop as coastal cliffs. They are also found in the numerous basalt quarries that have been worked around Melbourne and the western district during the past.
Cairns Bay at Flinders is world renowned for its zeolite specimens and occurrences. At Cairns Bay, high cliffs of basalt outcrop and form shore platforms extending into the ocean. The zeolites are most visible in the shore platforms, where they fill cavities in the basalt lavas. A number of varieties occur, including analcime, natrolite and mesolite.
Analcime is easily the most widespread species. On freshly cleaved surfaces, it forms lovely transparent crystals filling vesicles. When exposed to air and moisture, the crystals turn opaque white. The other main species occurring are natrolite and mesolite. The crystals occur as trapezohedrons, radiating clusters, globular clusters, fibrous and massive vesicle and vein fillings. The numerous boulders found on the shore platforms are often riddled with vesicle-filled, white analcime crystals. Veins of fibrous Natrolite and translucent Calcite are also widespread.
For the mineral collector, we recommend visiting Kitty Miller Bay, Phillip Island for collecting. Walking down to the beach from the car park, turn left onto the boulder-strewn shore platform and walk down to the old wreck around the headland. Near the headland and around the wreck, numerous outcrops of zeolites are evident.
A visit to Cairns Bay, Flinders, is worthwhile to view the abundance and diversity of Zeolite outcrop. There is a steep walk down to the beach. Turn left at the beach and walk down to the shore platform at the headland. Outcropping veins and vesicles filled with zeolites are abundant and widespread here.
The Museum of Victoria has released a book “Zeolites of Victoria” by Bill Birch, which explains the occurrence and properties of Zeolites in Victoria.
