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Hi Peter & All, May 2007
Garnets are relatively dense; garnet density 3.5-4.3; quartz density
2.6. In the May/June 2007 issue of Can. Geographic, a reddish beach in
Labrador is attributed to garnet. I suppose a heavier mineral might
become concentrated on a beach if lighter materials were swept away by
lateral currents.
When someone gets down there it would be interesting to test this
material. Organic would burn, reddish garnets will fuse in a blowpipe test.
Yt, DW
Peter Hope wrote:
> I just read all the email on pink sands. Brian is correct, they are
> fine particles of garnet. There are garnets in the neaby rock that are
> weathered out by wave action, etc and that reddish (garnet) colour is
> the typical colour of the mineral. The waves sort the materials and so
> bands, or thin layers of like materials are deposited together on the
> beach..
>
> When I dragged my toe through them these garnet layers were always on
> the surface so I had wondered and assumed they were lighter that the
> other beach materials. Anyway the idea is they are a different density.
>
> Pete
> ----- Original Message ----- From: "Brian Starzomski"
> <bstarzomski@gmail.com>
> To: <naturens@chebucto.ns.ca>
> Sent: Monday, May 21, 2007 3:27 PM
> Subject: Re: [NatureNS] Pink sands
>
>
>> Hi all-
>>
>> The general explanation given for the purple sands at the KSA is that
>> they are in fact heavy mineral sands as suggested by Ian (garnets, in
>> fact) weathered out of the Meguma Terrane rocks of the headlands near
>> the beaches.
>>
>> Cheers,
>>
>> Brian
>>
>>
>>
>> On 5/19/07, iamclar@dal.ca <iamclar@dal.ca> wrote:
>>
>>> Hi again, Sherman.
>>>
>>> I removed magenta from the pics, and the background tones became
>>> more natural on
>>> my screen, but the pink (more pale mauve, I'd say) remains on the
>>> outer beach.
>>> I think this might result from a sorting of heavy mineral sands
>>> (Zircon). But
>>> perhaps others are right about an organic origin. It is unlikely
>>> that beach
>>> sands would be anoxic enough and laden with sulphides to harbour
>>> "purple
>>> Cyanobacteria" (I don't know current taxonomic assigment), which
>>> produce this
>>> sort of colour on saltmarsh muds.
>>>
>>> Cheers, Ian McLaren
>>>
>>
>
>
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