This is a slight expansion of my letter “Q” contribution to the current weekly Alphabetical Series in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. In the 2021 version of this Series I also posted a Kakanui quartzite though of quite a different colour – see “Q is for Quartzite Stone from Kakanui”.
Q is for Quartzite
This stone appeared on Seadown Beach, Kakanui, North Otago, on 6 September 2024. In it, shades of grey form a backdrop to a dripping cascade of light yellow. I found quite a few good specimens of quartzite that day – see photos below which illustrate some of the diversity on this beach, though I have also at other times found a few red specimens:
Three red Kakanui quartzites found at other times:
One of my sources for the identification of this type of stone as quartzite is Jocelyn Thornton’s book “Gemstones” – on page 34 of the online version on “Beach Pebbles from Moeraki-Kakanui”, she shows one of these stones which she labels “Quartzite from Central Otago”. Another source is seeing a display of quartzites in the Birdlings Flat Gemstone and Fossil Museum:
Quartzite is a hard, metamorphic rock that forms when a quartz-rich sandstone is subjected to high heat and pressure over time. This process causes the quartz grains in the sandstone to fuse together, creating a dense, durable rock. According to most definitions, quartzite is composed of more than 90% quartz (see University of Auckland Geology). One of the characteristics of most of these Kakanui quartzites is the tiny clear quartz crystals or fragments that become visible in close-up photos.
The next Post in this Series is “R is for Rhyolite” featuring a spherulitic rhyolite from Slope Point. An Index for this Alphabetical Series is here.
One thought on “Q is for Quartzite”