Andradite (and all its different types)
Andradite comes in a multitude of colours ranging from greens and yellows all the way to deeper warm colours like oranges, reds, browns and more with different names for specific colour variants of the gem. With a hardness of 6.5 to 7.5 andradite garnets throughout history have been used in multiple ways from refractory materials and abrasives to decorative ornaments and jewels. Garnets aren’t always actually tested to find out what gem they are, some of the time they just put a name on it based on what it looks like. So at times an andradite garnet might actually be a grossular garnet but they label it andradite due to the market value being higher for andradite than grossular. Lower-quality or small stones are less likely to be tested than higher-value/collector-grade andradite gems. Named in 1868 by American geoscientist James Dwight Dana in honour of José Bonifácio de Andrada e Silva who in 1800 had discovered, described and named a “yellowish-grey mineral” which he found in a mine in Norway. He named the gem allochroite, (Greek αλλος-another, and χροια-colour,) description taken from one of the sources- “ due to the change of colour of the heated product (with sodium ammonium hydrogen phosphate, reagent in blowpipe analysis) when cooling.” which James Dwight Dana defined as a subvariety of andradite. Allochroite is now a synonym for Andradite. It is found in America, Italy, Mexico, Norway, Russia, Switzerland and many other places due to different variations of this gem. Andradite is often found covered or enclosed with other minerals: vesuvianite, chlorite, epidote, spinel, calcite, dolomite, magnetite, limestone, quartz and more. Andradite symbolised courage, strength and truth. It is heavily associated with the root “chakra”/energy source.
General images of Andradite below
Andradite types/variations
Andradite has multiple varieties of itself, made up of different properties and characteristics. There are 7 that I have found to be mentioned the most when researching about Andradite.
Colophonite- This gem used to be thought to be a variety of grossular garnet but has since been corrected to be a type of Andradite. Although with further research, that fact seems to swing back and forth with each sentence I read. It has a coarse granular texture being brittle and imperfect. It’s colours are warm tones of browns, reds, oranges and yellows. It’s an andradite made up of “complex silicate of calcium and ferric iron” from what I could find and understand.
Demantoid- Demantoid is a green variant of Andradite, getting its name from when it was first found and being called "Demant" which means "diamond" in old German. It was first discovered in Russia but has been found in Italy, Iran, China, Madagascar, Afghanistan and more. It has high refraction and dispersion which is where the comparison to a diamond came from, even with it’s difference in colour from any diamond. It’s green colour comes from an addition of chromium traces in the gem as well as at times ferric iron traces causing some yellowing.
Mali Garnet- This gem also has the name “grandite” and is also known just as the “Andradite-Grossular series”. It’s composition is between grossular (calcium aluminum silicate) and Andradite (calcium iron silicate). Although its predominantly grossular with the refraction index and hardness (refraction index having an average of 1.72-1.75 and a hardness of on average 7 to 7.5) which grossular is known more for, the andradite shines through with it’s amazing dispersion which andradite is known for. Mali garnets were first discovered in 1994 in Mali which has been the only found source of the gem. It’s colours range from golds to oranges, yellows and greens more commonly being known for the gorgeous olive green this gem can display.
Melanite- Melanite is the black variety of Andradite being named by Abraham Gottlob Werner in 1799, it was named after the greek word “melanos” meaning black. It can be found mainly in Mali, Mexico and California USA although it has been found in the pacific ocean during the Deep Sea Drilling Project in Hole 504B. This gem has higher traces of titanium oxide than regular andradite does.
Rainbow Garnet/Iridescent Andradite- First discovered in 1934 in Nevada USA, this variation of andradite has been known for some time with the most well known location being in Japan's Nara Prefecture in early 2004, which subsequently was closed of in august 2005 to protect the locality. It can since be found in Buskerud Norway, Nevada USA, Mexico, Russia and more. The rainbow shine is caused by extremely thin lamellae structures (from my research, lamellae structures are very thin layers of alternating materials causing many tiny diffractions of light making the rainbow/iridescent shine found in this gem) with alternating compositions of an andradite composition and a grossular-enriched composition.
Topazolite- A beautiful rare gem with colours of browns, oranges ,yellows and sometimes greens, the name Topazolite comes from its visual similarities to topaz. It’s golden colour is caused by the traces of ferric iron. This gem is found all over the world with some places being Germany, Italy, the USA and Madagascar, It is said to be the rarest variety of andradite. I can't find much information on this gem, but if there is anything worth adding please let me know.
Images of and in order-Colophonite, Demantoid and Mali Garnet below
Images of and in order-Melanite, Rainbow Garnet and Topazolite above.
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 :)
First one which is being written at current time and I picked a long one. I didn't realise just how many variations of Andradite there was until I started writing! Instead of getting 1 rock it ended up being 7! I should be able to get one or two posts out a week at the moment.
Thank you all for reading!
