"Fireworks stone" - Not actually Astrophyllite
On one of my recent treasure hunts for unique stones, I came across something that has been commonly coined as "Fireworks stone". I instantly fell in love - like falling in love with Nuummite. But why was this stone commonly interchangeable with Astrophyllite, which is gold, bronze and brown? The blues are striking, like the blues from an Anthophyllite, which can be seen in Nuummite.
With a cornucopia of questions and a new purchase, I started my scour of the internet. Here is what I came up with:
This is not, in fact, Astrophyllite. Now I know the word looks similar to Anthophyllite, which maybe could have played a part in it - lost in translation, maybe? Or it could be because the "spray" like patterns look similar.
My first stop, as usual, is mindat.org. Usually I can find a lead, and in this case I was luckier. Someone else had taken the liberty to get this stone tested back in 2022. Here are the results:
Here is their results listed on RockPTX: https://www.rockptx.com/fkm-376-to-fkm-400/#FKM-393
OK, maybe your thinking, "just tell me Mel".
The results are an Anthophyllite, Staurolite with (most likely) Almandine Garnet, and smaller amounts of Chlorite, Cordierite, and Quartz.
And what is one half of the main component in Nuummite? It is Anthophyllite.
I still felt the need to go further down the rabbit hole, as there has been a bunch of purported locations in which it comes from. I knew that there has been incidents of Nuummite found in Finland, which is commonly referred to as Jenakite in order to establish their own branding. So I found a PDF book of the "Gemstones of Finland", which can be found here:
Nuummite is on page 169 to 174, and I recommend taking a look because the images themselves show the beautiful array of what this stone can look like - sure enough that "Fireworks stone" looks uncanny. According to this book, "Electron microanalyzer examination has shown that the overall composition of yellow and orange nuummite is usually rich in gedrite, whereas violet, blue, and green variants are rich in anthophyllite" (pg 174). I thought this made sense that the Fireworks stone was so blue, as it matched the results from being primarily Anthophyllite. To further confirm that the stones from Finland and this Fireworks stone were the same, this book also mentions the same minerals that make up their Nuummite, "The iridescent amphibole content of the Paltamo nuummite gneiss is between 40 and 80 per cent. A more common amphibole mineral, hornblende, is another dominant mineral in the rock (meaning it constitutes over ten per cent of the material). The rock also contains cordierite and lesser quantities of garnet, plagioclase feldspar, quartz, chalcopyrite, chlorite, biotite, etc." (pg 173).
Well that explains a lot. I love this stone like Nuummite because it contains the sought after part of it - Anthophyllite.
I have researched more than just the couple of sources here, but I thought these were the most poignant. I have finally got to carve this stone and must say it is similar in the way the flashes appear and disappear, and that it needs to be cut on a particular angle for the flash to be prominent. It crumbles on a certain angle, probably because of the way the growth of this stone is structured.
I must say I am quite happy, though I will always love my Greenland Nuummite, it has sky rocketed in price over the years. This stone is quite a bit cheaper and the flash is absolutely out of this world!