Years ago I was on vacation with my family in the Adirondack mountains of northern New York State, and we visited an area where mica was mined. The ground was covered with shiny flakes, and it was mixed in with the soil. It could be mica flakes that you are seeing. It might be worth the effort to learn more about the local geology. To my knowledge, mica flakes are not toxic to plant life.

I agree, sounds like mica, or maybe shale particles.

It's just dirt.

Thanks! After doing a google search for mica, I'm certain that's what it is. :)

Vermiculite will give you shiny, glittery soil. If so, it would be a very good thing.

Sounds to me like someone used vermiculite in the past - it's a common seed starter and garden soil additive, and can wind up in compost if somebody dumped a dead potted houseplant into it.. Vermiculite eventually breaks apart into tiny individual sheets of mica. No problem there, except that it means the vermiculite has lost its ability to hold water.

Here's a little geology for anyone interested--more in-depth than necessary, but kind of neat I think:

The group of minerals to which vermiculite and the various micas belong, the phyllosilicates (or clay minerals), is interesting. There are two basic components: the SiOâ tetrahedra (T) and the XOâ or X(OH)â octahedra (O), in which X is a cation, usually Al or Mg. In a mica, two T layers surround an O layer, forming a sandwich, and multiple sandwiches are bonded by interlayer cations.

I think it's reasonable to think of micas and chlorites (very similar structure) as "complete" phyllosilicates, composed of repetitions of the entire T-O-T/interlayer cation sequence. They form in metamorphic and cooler igneous environments, and are moderately unstable at surface conditions, so they weather into other clay minerals. Clay minerals can sort of be lined up according to how much of the T-O-T/interlayer cation sequence is still intact; some minerals are T-O-T with no interlayer cations; some are T-O; some are just O. Depending on the exact structure remaining, it is possible for some of these minerals to capture water molecules and expand, or to hold onto varying amounts of nutrients in the form of cations.

Contrary to what demeter said above, vermiculite does not break into sheets of mica; mica weathers to vermiculite. Vermiculite can bond to water, whether it has been flaked into smaller pieces or not, because the bonding takes place at the molecular level.

The people who said mica are probably correct. It's not just that it's shiny, but also that if it's a phyllosilicate and you can see individual grains of it easily, there is a good chance it's mica, because when it weathers to other minerals, the grain size tends to get microscopically small.

Someone above also mentioned shale particles: shale is composed largely of clay minerals, including some micas, but in my experience, the micas flake off of the rest of the rock very easily so any shiny flakes in the soil may be mica that came out of a shale, but are probably not technically fragments of shale.

Thanks for the minerology weird! I've forgotten most of that over the years.

re mica and vermiculite, isn't ag vermiculite just mica that has been roasted till it expands? If someone dumped potting soil into the compost or on the ground, or used straight vermiculite in the garden, does that somehow bypass the normal weathering process? Or do you end up with the same thing? Academic I suppose, just curious.

When vermiculite is heated, it expands. To produce the vermiculite in the first place, mica has to weather or undergo hydrothermal alteration. Without getting too complicated, when micas are heated, they alter to feldspars (if there is enough Na and K around) and amphiboles (Mg and Fe).

I'm not exactly sure what you mean by "bypassing the normal weathering process."

Than answered the question, thanks. I was just trying to figure out whether potting soil vermiculite would look the same as weathered mica when mixed into soil.

We have raised beds made of stainless steel (my father was a sheet-metal worker! ), and I am finding just tons of small pieces of Mica. I call it my Mica garden; I think it's absolutely beautiful, it looks like gold! I have taken some inside and keep watering it and keep it in the sun. Will it continue to "grow"? Actually, I find it all over the soil around the house. I live in southern Michigan, and the grounds are pretty much rock. I'd like to know if anybody else has found pieces like this. They're only about 1/2 inch wide. Sandy Surface sandysurface@gmail.com

It will not grow, it's a mineral.

Vermiculite is actually heated up and expanded Mica. I came to this page because I want to find out about Micah mixed into my succulent soil because I have been actually mining Micah from the rocks in my yard. Don't laugh I have about 3 gallons of it ranging from half dollar and bigger chunks of it to smaller flakes the size of a dime it makes a beautiful top dressing for succulent pots. I have the clear Mica and also about two cups of black mica but I don't want to overload my succulents with any one mineral because I also make my own crushed granite. Lol.

Vermiculite is also not recommended as an amendment for succulent soil as it retains too much water

Hey, being in this quarantine I got bored LOL

Nice to have your own mica mine. I have a thin coal seam about 20 ft down, I suppose if I dug a hole I could heat my house with it. :-D

It's called Mica or Muscovite it is worth 2,000 per kilogram like 2.2 pounds really hard to get!

Sad story about children in Madagascar (as well as other places like India) mining mica and living in extreme poverty.

https://www.nbcnews.com/news/all/army-children-toil-african-mica-mines-n1082916

Most of this ends up in China to be used in products that end up in the West.

Not sure where mica in US potting mixes comes from, probably the western US or Canada rather than Africa/Asia.

Anyway I thought it was worth mentioning. We like to think things are getting better all over the world but in many ways for many people they're not.