This is my fifth contribution to the current Alphabetical Series in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. In the 2021 version of this Series I posted “E is for Entrance” (an “entrance” allows you to “look into” a stone, to see beyond its surface).
E is for Epidote
Epidote is a green mineral. I found this quartz-veined green quartzite on Gemstone Beach about 18 months ago – see “A Red, a Green and a Pink, Gemstone Beach, Wednesday 21 February 2024”. Its green is due to epidote. Epidote is also in many argillite stones on Gemstone Beach. When epidote is present in a rock, it causes it to have a green to yellow-green (pistachio-like) colour, sometimes quite deep and intense. It was named in 1801 by French mineralogist René Just Haüy (known as the Father of Modern Crystallography) from the Greek “epidosis” meaning “increase”, because the base of its rhombohedral crystal prism has one side larger than the other. For more, see Geology.com.
The next entry is “F is for Fossil Rhodolith in Fossiliferous Limestone”. An Index for this Alphabetical Series is here.
That is such a striking stone and a stunning example of why epidote with quartz veins is one of my favourite types of stones!