Grossular (and all it's variants)
Grossular is a gemstone that can be found in an impressive range of colours . It is said to have the largest variety of colours compared to other garnets, from warm browns and reds to light greens and even colourless (as well as oranges, yellows and even pink in one variety). The colour of this gem depends on the minerals that it can be found to have like iron, Chromium/Vanadium (different minerals but both cause green colouring) and manganese. Iron causing the gem to be more warmer colours yellows, oranges, reds and browns; Chromium/Vanadium causing different shades of greens and manganese causing orange to pink colours. Grossular garnets are calcium-aluminium silicates with the calcium and aluminium sometimes being partly replaced with iron. The gem has a hardness of 6.5-7.5 and is translucent to transparent with a glassy texture. It also can have visible inclusions such as zircon, actinolite or apatite. Once again like the last gem, grossular has many varieties all found in different locations with different names, colours, minerals, inclusions and so on. The most known varieties will have their own sections further on. This gem is found all over the world with just a few being Australia, Brazil, Canada, China, Kenya, Mexico, Russia, Sri Lanka, the USA and many more. This gem has been found multiple times throughout history without being named, first said to be found in 1790 in Russia then later in 1803 was documented and named by German geologist Abraham Gottlob Werner. It was named “Kanelstein” (German for "cinnamon stone") first due to the specimens being studied had more of a red colouring resembling cinnamon. It was later in 1808 updated to the name “Grossularite”, the name originates from the Latin word “Grossularia” which refers to the species of Ribes/Grossularia, Gooseberry. It’s name was then later in 1971 changed to the third and final name “Grossular”. Grossular symbolises prosperity, abundance and empowerment. It is heavily associated with the heart and root “chakras”/energy source.
General images of Grossular below. Pictures sourced from the website Mindat.org as well as an image from the National Museum of Natural History which i found shows the colours and changes really well and looks really cool.
General pictures
“This display at the National Museum of Natural History, Washington DC demonstrates the multiple hues grossular garnets can show. Photo by Alkivar. Public Domain.” from gemsociety.org
Grossular types/variantions
Like Andradite, Grossular has multiple varieties made up of different minerals.
Tsavorite- Discovered 1967 in Tanzania by British geologist Campbell R. Bridges, this gem gets its name from the place it was found near to, Tsavo National Park Kenya. Tsavorite was later given its name by the president of tiffany and co at the time, Henry B. Plattin in 1974. It has a gorgeous green colouring rivaling the looks of emeralds and was advertised as an alternative to such during a marketing campaign by tiffany and co in 1974, as an introduction to their new found gem entering the market. This gem has a hardness of 6.5-7.5 and gets its incredible green colour from traces of vanadium and chromium.
Hessonite- Hessonite also known as “cinnamon stone” is a gem with warm tone colours from yellow-orange to reddish-brown with its colouring being caused by the iron and manganese contents. Its origin and history is unknown with it being around for thousands of years and has roots in hindu culture. The origin for its name comes from the ancient greek word “hesson” meaning inferior. It was named that due to its slightly lower hardness compared to other garnets. There are not many sources for when the english name for it originated with the few there is saying early 1800s with the word deriving from the french word “essonit”. The current day most abundant sources/Localities for this gem are in Canada, Sri Lanka and Tanzania.
Leuco- This gem is a difficult one with not much recorded information yet is brought up whenever grossular variants are mentioned. Leuco gets its name from the greek word “leukos” roughly meaning white, clear and light with a few more words described when translating. Like its name, it is a colourless gem resulting from lack of any colour causing minerals such as iron, vanadium and so on. Primarily found in Tanzania but can and has been found in many more placed such as California, Canada, Mexico and Myanmar. There was no straight answer on its origin or discovery but it was said that the gem gained recognition in the late 20th century with its rarity and similar look to a diamond. It can have a cloudy appearance when raw and sometime have a slight tint of colour when there is very low traces of minerals.
Hydrogrossular- Hydrogrossular is a gem with the same composition as grossular, with hydroxide partly replacing the silica found in grossular. It has a hardness of 6.5-7.5 like the other variants and sometimes grows with idocrase/vesuvianite. This gem is translucent to opaque and is found in many colours all being caused by the same impurities as other grossular variants like iron, chromium, vanadium and manganese. It can also be colourless when there is little to no impurities. The gem was first discovered in 1908 but was originally misidentified, it was then officially identified and named in 1943 and was named for its hydroxide and water content. This gem can be found in South Africa, Canada, USA and China.
Merelani mint garnet- While first discovered in the 1960s this gem has only been more well known since the late 1980s. It’s name comes from it’s colour, a light mint green as well as where it was found, Merelani Hills of Tanzania. This gems colour comes from traces of vanadium and can also be found in kenya and madagascar.
Rosolite- Rosolite is a variant from mexico that is also known as “raspberry garnet” referring to its deep pink colouring. It’s pink colour is caused by traces of manganese. There is not as much information on this variant as there is with the others.
Viluite- Some sites say Viluite is a grossular variant while others only give answers about wiluite which is a variety of Vesuvianite.
Californite-Californite isn’t technically a grossular but infact a vesuvianite/ idocrase with a mix of grossular. It is mostly found in california which is where it gets its name from.
Mali garnet- This gem also has the name “grandite” and is also known just as the “Andradite-Grossular series”, this gem is written about more in the last post about andradite and its variants.
Images
Images of the gems in order: Tsavorite, Hessonite, Leuco, Hydrogrossular, Merelani mint garnet, Rosolite, Californite and Mali garnet.
I unfortunately couldn't find any images of viluite since i’m not sure on what it is or if the image I would find is actually the gem viluite.
This information is not my own nor are the images, I am not an expert. It was all found from various websites. If this actually gets seen feel free to ask for the websites I use and I will comment all the links. Please let me know if any information is incorrect and provide links to resources if possible :)
Sorry this one took agesss to post! I underestimated this rock. I left it until last possible minute not realising just how many variants it had! Instead of just writing about 1 rock I ended up researching and writing about 10 rocks! It's taken me a week T-T
I can't promise consistent posts while I'm writing about the garnets it seems, but I promise after the garnets are all done it will be quicker to write and there WILL be more posts!
Thank you all for reading!
