Anyone ever seen this before? Basically clear mica but with black smokey
looking intrusions, something geological in the way of tar/bitumen
leeching into the cleaving planes?

On Thu, 03 Nov 2016 16:41:17 +0000, N_Cook wrote:

Anyone ever seen this before? Basically clear mica but with black smokey
looking intrusions, something geological in the way of tar/bitumen
leeching into the cleaving planes?

Intrusions or *inclusions* do you mean?

On 03/11/2016 17:22, Cursitor Doom wrote:
On Thu, 03 Nov 2016 16:41:17 +0000, N_Cook wrote:

Anyone ever seen this before? Basically clear mica but with black smokey
looking intrusions, something geological in the way of tar/bitumen
leeching into the cleaving planes?

Intrusions or *inclusions* do you mean?


I'm no geologist, not erratics anyway.
Randomly distributed swirls like colours in marble, but smokey black colour

On Thursday, November 3, 2016 at 9:41:15 AM UTC-7, N_Cook wrote:
Anyone ever seen this before? Basically clear mica but with black smokey
looking intrusions, something geological in the way of tar/bitumen
leeching into the cleaving planes?

Sure; Amelia County, VA has some old mica mines, the native stuff is near black
(but that's 0.3 inch thick, and it's prepared by cleaving down to 0.003"
thickness).

On Thu, 3 Nov 2016, whit3rd wrote:

On Thursday, November 3, 2016 at 9:41:15 AM UTC-7, N_Cook wrote:
Anyone ever seen this before? Basically clear mica but with black smokey
looking intrusions, something geological in the way of tar/bitumen
leeching into the cleaving planes?

Sure; Amelia County, VA has some old mica mines, the native stuff is near black
(but that's 0.3 inch thick, and it's prepared by cleaving down to 0.003"
thickness).

So it's just availability? There's no special quality of black mica over
the regular stuff?

Michael

.....Just paint it black !

N_Cook a écrit :
Anyone ever seen this before? Basically clear mica but with black smokey
looking intrusions, something geological in the way of tar/bitumen
leeching into the cleaving planes?

On 04/11/2016 01:15, whit3rd wrote:
On Thursday, November 3, 2016 at 9:41:15 AM UTC-7, N_Cook wrote:
Anyone ever seen this before? Basically clear mica but with black smokey
looking intrusions, something geological in the way of tar/bitumen
leeching into the cleaving planes?

Sure; Amelia County, VA has some old mica mines, the native stuff is near black
(but that's 0.3 inch thick, and it's prepared by cleaving down to 0.003"
thickness).


I don't suppose you happen to know whether the insulation property is
just the same? I'm thinking whether the black material may absorb water
vapour

Pretty much all questions answered right he

https://en.wikipedia.org/wiki/Mica

Ontario seems to be one source of "Dark Mica".

Some types do absorb moisture, but, it is not as if they would be used for insulators.

The original "Glitter".

Peter Wieck
Melrose Park, PA