Stone Eleven is a green hydrogrossular garnet. It was found on Gemstone Beach early in March this year, only a couple of hundred metres from the car-park, on the edge of Taunoa Stream. It is still undergoing the polishing process, having just come out of the pre-polish tumble and about to go into the final stage, the pro-polish tumble.
I had planned to highlight hydrogrossular garnets as one of the three main polished stones from Gemstone Beach in the display I was preparing for the now-cancelled Whanganui Rock and Mineral Club Show later this month. The photos below are of a rough mock-up of the display in my office at home.
I had written the following to accompany the stones:
Gemstone Beach is most well-known amongst collectors and craft jewellers for the hydrogrossular garnets that can be found there. Unlike the garnets we know as precious gems, hydrogrossular garnets come from dense masses, not crystals. Generally, a hydrogrossular stone has some transparency (you can see some light through it) and it feels waxy. It shines brightly on the beach when wet. The “grossular” part of its name is derived from the Latin word for gooseberry, because of the light-green colour of many hydrogrossular stones. However, white and brown are two other common colours, with pink and grey also known. Hydrogrossular stones are easily polished and make excellent pendants. Maori used hydrogrossulars as hammer-stones because of their hardness. Garnets are types of stones which tend to form in metamorphic rock, under intense heat and pressure. Technically, hydrogrossular garnets are a calcium aluminium garnet with hydroxide partially replacing silica. The other main place to find hydrogrossular in New Zealand is around Nelson. The first ever identification of hydrogrossular garnet in the world was in 1943 from Nelson, and it is the most widely spread of the 13 minerals first described from New Zealand.
Stone Eleven is pendant-shaped and is a medium-sized stone. When held up to a light source, it is only partially translucent, with light being able to shine through solely along the thinner edges.
For more on hydrogrossular garnets, see my previous Posts, What are Hydrogrossular Garnets?, Why are Hydrogrossular Stones Called Garnets? and Why are Hydrogrossular Garnets found in Nelson and Orepuki?
Note: The next Post in this Series is Stay-at-Home Day Twelve, Monday 6 April 2020: Stone Twelve. The first Post in this Series of Stones is Stay-at-Home Day One.
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