[Rockhounds] Beryl Pit Beryl

[Tim Jokela Jr.]

Quadeville beryl varies from glassy gem deep blue aquamarine, to ugly 
greens, yellows, and browns, to soft brownish partial to complete 
pseudomorphs. I think it's safe to say that radiation is not the cause of 
the beryl's deterioration. Hydrothermal alteration is the more likely cause, 
the evidence being the abundance of bertrandite, formed by the dissolution 
of beryl. The abundance of deeply altered pyrite, 1-3cm cubes replaced by 
deep brown goethite, with only a small core of fresh brassy pyrite left, 
suggests the same. The pegmatite has been dated at 1.1 billion years old, so 
plenty of time for water to do its thing.

Sinkankas, in Emerald and Other Beryls, gives many localities for beryl 
altered and replaced by other minerals (pp.173-175). He also lists a wide 
variety of color changes caused by irradiation and heat treatment 
(pp.228-230). The changes are fairly complex, and variable, but I think it's 
safe to say that irradiation of beryl can change the color but not the 
luster or clarity. (Lots of lustrous transparent and highly radioactive 
minerals out there.)

I'm not sure of the cause of the color of the brick red feldspar. It is 
certainly home to a lot of radioactive euxenite-(Y), zircon, allanite-(Ce), 
and others, but I don't recall whether anybody has proven a correlation.

Cheers,

Tim Jokela Jr., tjokela at execulink.com
Business: http://www.element51.com
Pleasure: http://www.ontariominerals.com

----- Original Message ----- 
From: "Carolyn Reynard" <sunstone3 at hvc.rr.com>
To: "Rockhounds at drizzle.com: A mailing list for rock and gem collectors" 
<rockhounds at lists.drizzle.com>
Sent: Sunday, January 13, 2008 8:43 PM
Subject: Re: [Rockhounds] Beryl Pit Beryl


> Tim,
> The beryl I have collected at the Beryl Pit in Quadeville, Ontario has 
> been
> an opaque unattractive greenish brown in deep red-brown feldspar. Since
> there are some radioactive minerals in that quarry namely euxenite and
> allanite I thought the condition of the beryl was due to radiation.
>
> Some of the beryl crystals I collected there are as long as 1.5 to 2 
> Inches
> long and they tended to be tapered, a bit like teasan quartz crystals.  I
> came home with an interesting crystal of a amphibole crystal .5" x 2" 
> which
> may be hornblende. But that crystal too appeared to be altered as it is
> opaque limonite ocher and hematite brown with intergrown small lustrous
> schorl crystals. The crystal was imbedded a large specimen of fragile thin
> platy iridescent clevelandite and quartz.
>
> My question is:  What are the observed effects of radiation of beryl? 
> Would
> they cause it to be dull and opaque? Is it correct to say the deep brick
> red-brown of feldspar is due to radiation?
>
> Carolyn Reynard
> Poughkeepsie, NY
>
>
>
> ----- Original Message ----- 
> From: "Tim Jokela Jr." <tjokela at execulink.com>
> To: "Rockhounds at drizzle.com: A mailing list for rock and gem collectors"
> <rockhounds at lists.drizzle.com>
> Sent: Sunday, January 13, 2008 1:07 PM
> Subject: Re: [Rockhounds] Beryl Pit Beryl
>
>
>> At the Beryl Pit, near Quadeville, north of Bancroft, Ontario, a lot of
> the
>> beryl is indeed replaced by a number of minerals, including clay, mica,
>> chlorite, and very minute bertrandite xls, so that what was once a very
> hard
>> mineral is now soft, crumbly, or even waxy. A white acicular mineral has
>> also been found, very rare and tiny, and still requires analysis. Relict
>> beryl, masses or interesting very fine needles, is also present. 45x is
>> required to appreciate all the replacement minerals.
>>
>> Micromounters should seek out the rotted beryl, for the vugs around it 
>> are
>> home to the finest bertrandite crystals, and are where we expect to find
> Be
>> minerals new to the locality. Collecting remains excellent at the Beryl
> Pit,
>> for those interested in unusual or micro things at least. Hard work and
>> close examination are key.
>>
>> Tim Jokela Jr., tjokela at execulink.com
>> Business: http://www.element51.com
>> Pleasure: http://www.ontariominerals.com
>>
>> ----- Original Message ----- 
>> From: <SMKELL45 at aol.com>
>> To: <rockhounds at lists.drizzle.com>
>> Sent: Sunday, January 13, 2008 12:16 PM
>> Subject: [Rockhounds] Beryl Pit Beryl
>>
>>
>> > I've been visiting the Beryl Pit for the last couple of summers. The
> beryl
>> > that I find is not green but  dark brownish, obviously altered. There
>> > doesn't
>> > appear to be any crystal structure ,at least not with a 10 power lens.
>> > Has
>> > anyone come across this material and if so what have you determined it
> to
>> > be?
>> >                 smkell
>> >
>> >
>> >
>> > **************Start the year off right.  Easy ways to stay in shape.
>> > http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
>> >
>> >
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