Hematite on Edenite, New Zealand

Mineral Matters #451

This week’s Facebook Mineral of the Week Group theme is minerals in the Amphibole Supergroup. Igneous rocks can be a good source of amphibole species of varying types.

Hendersons Quarry, Mount Ngongotaha, near Rotorua on New Zealand’s north island, has a number of amphibole species recorded. The quarry is made up of several igneous rock types including pumice, obsidian and rhyolite. Crystalline minerals occur in lithophysal cavities in the rhyolite zone.

One of my favourite amphibole species from here is edenite, but a form that occurs as very thin hair-like crystals, often curved, looking like they are the most fragile things. But then having balls of hematite strung along them!

This specimen, and my apologies for the (very) old photo, was collected by me back in 2007. I must dig the specimen out and retake it!

Below: Hematite, Edenite, Hendersons Quarry, Mount Ngongotaha, Rotorua District, Bay of Plenty Region, New Zealand. Width of view 2mm.

Below: A view from high up in the quarry.