FMF - Friends of Minerals Forum, discussion and message board

[Donn C.]

Wondering about the crystal formation dynamics involved in Quartz crystals forming into this hexagonal ring formation??? Why do they form these rings in simple terms….. This piece has 7 rings in the group. I have found a few of these over the years.

[Eck Noch]

It’s hard to tell, but I’m not seeing actual concentric rings of Quartz, I do see the outer ring of crystal growth but the inner growth seems more randomized. That being said, I have several pieces of self collected Quartz who’s growth was interrupted by calcite, it does have raised ridges of concentric lines, if this or something similar were the mechanism of growth, that I could absolutely see the Quartz growing that way! But what a cool piece. I’ll see if I can find the rocks In my yard to show this.

[Eck Noch]

Here, found it. Calcite interrupted Quartz growth.

[Bob Morgan]

Was this found in a small vugh or cavity or on a wall of a bigger space where mineralizing fluids might have flowed?
It appears that there were perhaps faster growth conditions with other places having crystals growing in all directions from a center. If so, these might be built by skeletal growth similar to crystals from Mule Creek, Grant County, New Mexico. They, in most extreme cases, have outer hexagonal walls with almost random growths in hollow insides.
Another possibility is that of dissolution of larger crystals more on the r and z terminal faces carving out the crystals and redeposition to finish off all the crystals as they now appear. That looks less likely to me in this case.
It is a wonderful find to spark mystery and research. Quartz sure can do that!

[Donn C.]

[Eck Noch]

Another angle of the same rock.

[Eck Noch]

That’s really fascinating growth. Have me stumped for sure!