Op 10/09/2021 om 22:36 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 10/09/2021 om 01:26 schreef Samuel B.:
>>> Hey, is that a classic Estwing hammer I see? (...)
>>>
>> Yes sir, it is! Modelled on my own, old, specimen, which has accompanied
>> me for the last 55 years or so. Got it for my birthday after I had
>> revealed to my parents that I intended to be a geologist.
>>
>> It is also worn down, probably not as much as yours.
> 
> You can be the judge of that... I've attached a photo of mine for your viewing
> (dis?)pleasure. As you can see, it's fairly worn. Not too bad, but reshaping it
> means losing some length from the pick. But the worst part is the condition of
> the handle... It needs the for the lacquer to be removed and some oil applied.
> I've dug underwater in creeks with the thing, to loosen rocks and get at
> gold-bearing clay, so it's no wonder it looks like it does. (One time when I was
> doing this - my chin partially underwater - an otter popped its head over some
> boulders, saw me, and quickly went the other way, lol.)
> 
Well... except for the handle, mine is in the same condition, with some 
serious dents in the head additionally (from hitting too many quartzitic 
rocks in Scandinavia and the Alps iirc). That handle of yours needs some 
refurbishing indeed. As you say, some oil for the leather to absorb. 
After a hot field summer in Spain, the leather had started to shrink and 
crack, a bit like yours. I used to dip it in a water pool for a couple 
of hours... Otherwise, your Estwing still looks pretty operational. I 
don't know about reshaping the point. Generally, it doesn't need to be 
too sharp (or it looses its sharpness pretty soon anyway).

>> Its most intensive
>> use was during my studies when fieldwork was in hardrock countries
>> almost exclusively. Later, as I switched to softrock specialisation, it
>> gathered mostly dust. Trowel & spade took over. :-)
>  > Yeah, a rock hammer isn't often the best tool for everything, that's 
for sure.
> My other main tool is a long, flat-headed screw driver. Perfect for prying apart
> rocks that would otherwise be difficult to budge. (But I've chipped a bunch of
> quartz crystal terminations doing that...)
> 
Screwdrivers, chisels, whatever is available. Hardware stores are little 
paradises for that ;-)

>> However, it is still there, sometimes to be used when a rock passes by.
>> Never took it on a plane though; you can imagine why...
> 
> Tomorrow is one of the reasons why, I'm guessing?
> 
Yeah...

>>> Not many minerals around here except for granitic rocks, (...)
>>>
>> The Sierra Nevada, I assume. Fascinating geological history over there.
> 
> Yep! It's just too bad there's not much interesting going on in my immediate
> locale. I'd really like to spend some time in some of the more interesting
> places, like Fresno Country, Inyo County and even San Diego County, even though
> the latter has been heavily prospected. Inyo seems like the best bet for
> undiscovered treasures.
> 
Not sure but I guess areas on the fringes/just ouside of the granite 
outcrops would be more promising, and the metamorph, ancient sedimentary 
rocks?

>> You did some perfect modelling of jasper and topaz.
> 
> Oh, that reminds me. I know your specialty is more on the geological side of
> things, but a great tool has just become available for free: KrystalShaper (
> http://www.jcrystal.com/products/krystalshaper/ ) It provides a catalog of
> hundreds of minerals, plus tools to analyze and export geometry. Might be worth
> checking out.
> 
I shall do that.

>> Your Europan vacation shot still fills my background screen here, btw.
> 
> Haha, cool. I still want to update that scene with a camping tent, RV or
> something.
> 
>>> What do you plan to use the granite for, if anything?
>>>
>> No real plans at the moment. My primary intention was to finally put
>> Daniel Mecklenburg's code to good use after all those years.
> 
> I'm out of the loop, so I'm not sure what that entails, but I'm looking forward
> to seeing it.
> 
Sorry, my bad, you are already ;-) What I meant is that the Granite_21 
macro is the result of wanting to turn Daniel's code into proper 
granites for a number of years.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Generally, it doesn't need to be too sharp (or it looses its sharpness pretty
> soon anyway).

That's probably exactly how it should be, since tools that keep an edge are
generally very brittle... a property you might not want in hammer ;)

> Not sure but I guess areas on the fringes/just ouside of the granite
> outcrops would be more promising, and the metamorph, ancient sedimentary
> rocks?

You would be right, since those have always been the most interesting spots,
ime. Once in Fresno county, we found some marble. I've never seen marble with
such large grains. Right next to that we found garnet clusters (grossular,
probably). And then we began finding epidote, more garnets, and very beautiful
smokey quartz near some mines.

In the lower elevations of this general area, almost everything is hydrothermal
and metapmorphic. You'll find shale with fossils, slate a ways off from the
shale, quartz veins running through both, soapstone in one area and serpentine
(an altered form of soapstone iirc) in another. Pyrite, gold, even pure sulphur
in some places. It's crazy.

And there's an area near a river which I suspect might be harboring corundum. In
that place you can find marble outcrops above an area with granite pegmatite (I
might have found a green beryl there as a kid but it's been lost). Since I
figured corundum is sometimes found in marble, and considering the prevalence of
aluminum in the area (micas, soap stone, etc.), I thought that maybe rubies and
whatnot could be possible as well.

Sam

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Op 10-9-2021 om 22:36 schreef Samuel B.:
> Oh, that reminds me. I know your specialty is more on the geological side of
> things, but a great tool has just become available for free: KrystalShaper (
> http://www.jcrystal.com/products/krystalshaper/ ) It provides a catalog of
> hundreds of minerals, plus tools to analyze and export geometry. Might be worth
> checking out.
> 
Nice little program indeed! Thanks. Wulff-nets, ha! That was not really 
my cup of tea... ;-)

The output could be the basis for crystal renders of quality. Not much 
time at the moment, but I keep in mind.

-- 
Thomas

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Attachments:
Download 'quartz.png' (48 KB)

Preview of image 'quartz.png'

Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 10-9-2021 om 22:36 schreef Samuel B.:
> > Oh, that reminds me. I know your specialty is more on the geological side of
> > things, but a great tool has just become available for free: KrystalShaper (
> > http://www.jcrystal.com/products/krystalshaper/ ) It provides a catalog of
> > hundreds of minerals, plus tools to analyze and export geometry. Might be worth
> > checking out.
> >
> Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
> my cup of tea... ;-)

I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
me convert HKL values to planes...

> The output could be the basis for crystal renders of quality. Not much
> time at the moment, but I keep in mind.

What's your camera aspect there? The crystal looks stretched vertically.

It is a cool program, I just wish I could figure out my HKL issues so I can do
more with it. (My previous searches didn't turn up much useful info, or maybe I
wasn't comprehending what I saw...)

Sam

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Op 14/09/2021 om 01:14 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 10-9-2021 om 22:36 schreef Samuel B.:
>>> Oh, that reminds me. I know your specialty is more on the geological side of
>>> things, but a great tool has just become available for free: KrystalShaper (
>>> http://www.jcrystal.com/products/krystalshaper/ ) It provides a catalog of
>>> hundreds of minerals, plus tools to analyze and export geometry. Might be worth
>>> checking out.
>>>
>> Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
>> my cup of tea... ;-)
> 
> I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
> some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
> me convert HKL values to planes...
> 
That is correct. It is/was used in crystallography for mapping mineral 
indices and do all sort of exciting things, calculating angles and 
intersections. Only, as a freshman, I was not particularly interested in 
this branch of geology! Hammering away at overturned, anticlinal rock 
sections: /That/ was what life was about! ;-)

But seriously, I do not remember how it worked exactly but it certainly 
could be of help to you I guess. I still have a Wulff net somewhere 
here, gathering dust.

>> The output could be the basis for crystal renders of quality. Not much
>> time at the moment, but I keep in mind.
> 
> What's your camera aspect there? The crystal looks stretched vertically.
> 
For the demo image I didn't bother with the scene details; just used the 
standard scene code provided by the app.

> It is a cool program, I just wish I could figure out my HKL issues so I can do
> more with it. (My previous searches didn't turn up much useful info, or maybe I
> wasn't comprehending what I saw...)
> 
I know what you mean. These are a couple sites which explain the use of 
the Wulff net. There are more of course, but these are fairly basic.

http://www.minsocam.org/ammin/AM25/AM25_689.pdf
https://www.doitpoms.ac.uk/tlplib/stereographic/wulff_construct.php

However, to tell the truth, I remain a bit baffled when I see those 
things again, after all those years. I am not really sure I understand; 
I think you are more familiar with all this.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> (...)
> Only, as a freshman, I was not particularly interested in
> this branch of geology! Hammering away at overturned, anticlinal rock
> sections: /That/ was what life was about! ;-)

Yeah, being out in the field is wonderful. I know our reasons for being out
there were for different reasons, but I also know the thrill of finding
something interesting and tracking it down. I really miss it.

> Op 14/09/2021 om 01:14 schreef Samuel B.:
> > It is a cool program, I just wish I could figure out my HKL issues so I can do
> > more with it. (My previous searches didn't turn up much useful info, or maybe I
> > wasn't comprehending what I saw...)
> >
> I know what you mean. These are a couple sites which explain the use of
> the Wulff net. There are more of course, but these are fairly basic.
>
> http://www.minsocam.org/ammin/AM25/AM25_689.pdf
> https://www.doitpoms.ac.uk/tlplib/stereographic/wulff_construct.php
>
> However, to tell the truth, I remain a bit baffled when I see those
> things again, after all those years. I am not really sure I understand;
> I think you are more familiar with all this.

No, I don't think I'm any more familiar with these things than you are...
probably less so. Thanks for the links. But I looked at them and to be honest,
the information looks very thick. So thick I'm not actually sure if it would be
any help in my endeavors...


Sam

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Op 16/09/2021 om 01:23 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> (...)
>> Only, as a freshman, I was not particularly interested in
>> this branch of geology! Hammering away at overturned, anticlinal rock
>> sections: /That/ was what life was about! ;-)
> 
> Yeah, being out in the field is wonderful. I know our reasons for being out
> there were for different reasons, but I also know the thrill of finding
> something interesting and tracking it down. I really miss it.
> 
I can understand that.

>> Op 14/09/2021 om 01:14 schreef Samuel B.:
>>> It is a cool program, I just wish I could figure out my HKL issues so I can do
>>> more with it. (My previous searches didn't turn up much useful info, or maybe I
>>> wasn't comprehending what I saw...)
>>>
>> I know what you mean. These are a couple sites which explain the use of
>> the Wulff net. There are more of course, but these are fairly basic.
>>
>> http://www.minsocam.org/ammin/AM25/AM25_689.pdf
>> https://www.doitpoms.ac.uk/tlplib/stereographic/wulff_construct.php
>>
>> However, to tell the truth, I remain a bit baffled when I see those
>> things again, after all those years. I am not really sure I understand;
>> I think you are more familiar with all this.
> 
> No, I don't think I'm any more familiar with these things than you are...
> probably less so. Thanks for the links. But I looked at them and to be honest,
> the information looks very thick. So thick I'm not actually sure if it would be
> any help in my endeavors...
> 
Yeah... I know what you mean. One of the reasons I didn't get very far 
in crystallography. I have some 3D visualisation skills :-) but these 
kind of exercises always left me profoundly baffled I confess. Otoh, I 
believe they /may/ unlock certain geometrical symmetry problems proper 
to certain mineral classes.

-- 
Thomas

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"Samuel B." <stb### [at] hotmailcom> wrote:

> > Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
> > my cup of tea... ;-)
>
> I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
> some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
> me convert HKL values to planes...
>

> It is a cool program, I just wish I could figure out my HKL issues so I can do
> more with it. (My previous searches didn't turn up much useful info, or maybe I
> wasn't comprehending what I saw...)


Aren't the HKL values just the vector normals of the planes?
That's what the wikipedia articles suggested on my brief skim.

Would not plane {y, 0} have an hkl index of <0,1,0>?

Not sure what the overall goal is, so not sure what to suggest to test this.

- Bill

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Op 16-9-2021 om 12:28 schreef Bald Eagle:
> "Samuel B." <stb### [at] hotmailcom> wrote:
> 
>>> Nice little program indeed! Thanks. Wulff-nets, ha! That was not really
>>> my cup of tea... ;-)
>>
>> I don't even know a Wulff net is. But based on its appearance, I'm guessing it's
>> some sort of mapping between HKL indices and a sphere. Maybe it's a clue to help
>> me convert HKL values to planes...
>>
> 
>> It is a cool program, I just wish I could figure out my HKL issues so I can do
>> more with it. (My previous searches didn't turn up much useful info, or maybe I
>> wasn't comprehending what I saw...)
> 
> 
> Aren't the HKL values just the vector normals of the planes?
> That's what the wikipedia articles suggested on my brief skim.
> 
> Would not plane {y, 0} have an hkl index of <0,1,0>?
> 
> Not sure what the overall goal is, so not sure what to suggest to test this.
> 
If I remember correctly, that is indeed the case I believe.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:

> > Aren't the HKL values just the vector normals of the planes?
> > That's what the wikipedia articles suggested on my brief skim.
> >
> > Would not plane {y, 0} have an hkl index of <0,1,0>?
> >
> > Not sure what the overall goal is, so not sure what to suggest to test this.
> >
> If I remember correctly, that is indeed the case I believe.
>
> --
> Thomas

So then, to some degree, the unit cell for the crystal should be some form of
intersection between all of the planes that the hkl indices define. (?)  Does
the file format include any data that would serve as an offset?

Creating the most basic crystal shapes, probably starting with cubic NaCl, might
give a clue as to how to code an implementation of that notational system.

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