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bailey1
Joined: 01 Jan 2010
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Location: virginia
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Posted: Jan 01, 2010 18:23 Post subject: Seeking info on hyalite |
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Hello. I am doing a small school project for my 9th grade class. I had to choose a mineral, and I chose hyalite. I now have to answer questions about it, and am finding very little info on hyalite.
If someone could help me some, that would be great. Thanks.
What is the crystal form of hyalite?
What is its mineral family? I read it is an opal....does that make sense? What is the mineral habit? What are the major physical properties? Where is it found? And what might it be used for?
Thanks in advance for any help you might give.
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Peter Megaw
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Posted: Jan 01, 2010 18:53 Post subject: Re: seeking info on hyalite |
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Bailey, hyalite is not exactly a mineral...it is a colorless variety of opal that looks like clear jelly...silicone sealer, or the gross stuff that comes out of the top of a can of pet food. It typically forms in volcanic environments from degassing and devitrifying piles of rhyolitic welded ash-flow tuffs (aren't you glad you asked?... geologists use a lot of complicated words when simiple ones might work just as well.). "rhyolitic ash-flow tuffs" tells us composition (rhyolite is the volcanic equivalent of granite the principal ingredient of the earth's continental plates...the light ones that "float" on the denser oceanic basaltic plates. Ash-flows are the products of an incredibly violent form of volcanic eruption where thousands of cubic kilometers of gas-rich magma is erupted almost instantly...like opening a well-shaken can of coke...only what comes out is at about 900 degrees celsius and traveling at near the speed of sound. You will NOT get out of the way of one of these. Lately these have been referred to as "super-volcanos" or mega-volcanoes...one of these formed Yellowstone and may go off again in the geologically near future (don;t wait up nights though). Rhyolite is very rich in silica and as it is blasted out of the volcano as an incandescent froth it chills instantly to glass...but it's still moving in a stream of hot gasses, so partles of ash flow out over the countryside and blanket thousands of square kilometers of land around the volcano and begins to settle and cool to a hard rock (hence "welded ash-flow"). This is where hyalite comes in...as the pile settles and cools, the hot gasses trapped between glass particles are forced out ("degassing") and they chemically attack the glass bits (which are chemically unstable like all glass is...glass is just a quenched liquid that cooled too fast to crystalize, which is the physico-chemical state it would much prefer to be in) and the chemical ingredients (mostly silica) of the glass "dissolve" in the hot vapors (= "devitrification...or "de-glassing"). These laden vapors travel through the volcanic pile until they reach some kind of open vent...fissure, gas tube, large gas bubble etc...and the gas cools enough for the silica (with water from the hot vapors) to form opal. If the opal is colorless jelly, we call it hyalite, if it has plays of color we call it precious opal, if it forms opaque white masses its common opal. I suspect if you go to www.mindat.org you can find out a lot about opal...including hyalite. One of the other cool things about hyalite is that rhyolites tend to contain just a trace of uranium (way too little to make a bomb or hurt you, but still enough to be detectable) which "activates" brilliant yellow-green fluorescence under an ultraviolet light (black light)...so it goes from colorless jelly to brilliant yellow-green jelly making it much more interesting. I will see if I can get you a before and after shot of hyalite
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vic rzonca
Joined: 18 Nov 2008
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Posted: Jan 01, 2010 19:18 Post subject: Re: seeking info on hyalite |
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well done !
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bailey1
Joined: 01 Jan 2010
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Location: virginia
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Posted: Jan 01, 2010 19:26 Post subject: Re: seeking info on hyalite |
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Thank you very much. Would you mind answering my questions in simpler words though? I really only need those questions answered. I tried looking on Google for an hour or two and it is very hard to find the answers. Thank you!
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Jordi Fabre
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Posted: Jan 01, 2010 19:37 Post subject: Re: seeking info on hyalite |
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Check here -> https://www.mindat.org/min-1959.html
Jordi
Description: |
Here you have a photo published here ( http://www.mineral-forum.com/message-board/viewtopic.php?p=2776#2776 ) In fact they are Lussatite after Hyalite, but they looks like Hyalite... |
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bailey1
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Posted: Jan 01, 2010 19:41 Post subject: Re: seeking info on hyalite |
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Thank you very much, but all I need answered is the questions I asked above. Could anyone answer them in simple words? I would be so grateful. Thanks in advance!
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Jordi Fabre
Overall coordinator of the Forum
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Posted: Jan 01, 2010 19:54 Post subject: Re: seeking info on hyalite |
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Bailey,
You have answers to all your questions in the link I sent to you as well as in the fabulous text written by Peter Megaw.
Please read both carefully and work with they, otherwise us we will do your school job and this is not the function of this Forum.
Jordi
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bailey1
Joined: 01 Jan 2010
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Location: virginia
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Posted: Jan 01, 2010 20:20 Post subject: Re: seeking info on hyalite |
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Thank you both of you, especially Peter. :)
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Amir Akhavan
Joined: 01 Dec 2009
Posts: 95
Location: Hamburg
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Posted: Jan 01, 2010 20:39 Post subject: Re: seeking info on hyalite |
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O.k., short
- What is the crystal form of hyalite?
None. It is amorphous.
- What is its mineral family?
It depends on the classification scheme, there are many.
Check https://www.mindat.org/min-3004.html
under "Classification of Opal"
- I read it is an opal....does that make sense?
Yes, it is an Opal. It is called opal-AN. That translates to "opal-amorphous-network-like internal structure"
It's structure is not unlike glass and its water content is relatively low, which is different from the other forms of opal that may contain up to about 10% water.
If it had been recently discovered, opal would not be called a mineral any more, because it is not cristalline, but amorphous. Some people would say it is a mineraloid. It's only called a mineral because of respect for some traditions and old classification schemes.
((( does it make sense - hmm. I could start a rant now on how two substances as different as opal-CT and opal-AN can be called a variety of a single mineral species that is not a mineral. But I don't start a rant. )))
- What is the mineral habit?
The habit is typically botryoidal.
- What are the major physical properties?
Check https://www.mindat.org/min-3004.html
under "Physical Properties of Opal"
Different from the other opals (like precious opal), it usually shows no or only very little opalescence. That has to do with its glass-like structure. Precious opal (a form of so-called opal-AG) is made of tiny spheres embedded in silica which causes the play of colors.
- Where is it found?
Peter has written a lot on that.
One might add: Opals cannot be found in old rocks (more than 50-100 million years), because they slowly transform into quartz.
And what might it be used for?
As far as I know, there's no technical use for it. It is worthless as a gem, because it does not show "opalescence". So it is just a collector's item.
Amir
Description: |
Hyalite. Valeĉ, Czech Republic. Feld of view about 2.5 cm. |
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_________________ Amir C. Akhavan, Hamburg, Germany |
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bailey1
Joined: 01 Jan 2010
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Location: virginia
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Posted: Jan 01, 2010 20:44 Post subject: Re: seeking info on hyalite |
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THANK YOU! I've been working on this for hours with my mother. I've learned a lot, but thank you so much for your clarification. :))))
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Peter Megaw
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Joined: 13 Jan 2007
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Posted: Jan 01, 2010 23:13 Post subject: Re: seeking info on hyalite |
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Bailey, I understand your frustration with the language, but before you feel swamped, understand that geology/mineralogy like most sciences (and perhaps more than many) has a vocabulary that gives a foreign language a run for its money...they say you learn more new words in the first year of geology than in 3 years of a foreign language. Also understand that, like being in a foreign country, you can't converse readily at a sophisticated level until you've got the basics. To an outsider (someone not yet steeped in the vocabulary...perjoratively termed jargon) this can seem deliberately exclusive, but it isn't, it's just the language we use daily to communicate with others...who presumably operate at a similar level. Quite innocently, you have bitten off a subject (hyalite) that is a topic of significant philosophical and scientific bebate amongst the insiders...and you've asked your question of a nest of insiders many of whom are wading in with highly sophisticated information on the subject! Had you chosen quartz or calcite your life would be much easier...on the other hand that's ALL you would have learned about...we hope this has given you a good peek behind the curtain and that you like what you see...we're here to help you see more, it's how we all got brought in in the first place.
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Peter Megaw
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Posted: Jan 01, 2010 23:15 Post subject: Re: seeking info on hyalite |
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BTW: Bailey's Mom, we hope you've learned a lot too...check out some of the other threads here, you might find some kindred spirits! Thanks for being there for her/him.
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bugrock
Joined: 24 Nov 2008
Posts: 137
Location: Michigan
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Posted: Jan 02, 2010 01:42 Post subject: Re: seeking info on hyalite |
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Bailey and Mom (and all responding),
Your questions pose some interesting thoughts:
Science:
1) Science (and not necessarily "modern" science) can present a barrier to those not familiar.
2) But science is the process of asking questions and trying to answer them and many scientists will freely
admit they do not have all of the answers. Otherwise they would be left with nothing to do!
Bailey, do not be afraid of asking more questions. Keep at it. You only make those scientists think harder!! A good thing.
Perhaps one day you will be a scientific writer. You could serve the purpose of explaining science to others.
Education:
1) Very curious why you chose the mineral you are interested in. Was it picked from a list, do you have a
specimen? Hmm... and why over the Holiday Break? Break assignment, home school?
2) The way you pose your questions suggests the teacher gave you a list of questions to answer.
If so you have my permission to go back to the teacher with the request of asking to attend a mineral show or museum
in your area or to invite someone to come to your school to talk about geology and minerals. Then, based on
what you discover or have questions about, YOU choose the subject and you come up with the questions to ask/answer.
Bailey,
It's up to you. Fill in the blanks and submit that assignment. Or ask the teacher to let you go further!
(And Mom, sounds like you have been offering a bit of help here, your child needs to learn the
scientific process, rote answers will not quench curiosity.)
OK, one more thought from someone who did not grow up on the internet.
Have you sought out books/articles at your library to answer your questions?
There is much on the internet no doubt. But books put together information,
thoughts, and methods. Start there and then go to the internet to learn more,
fill in details etc. Or you might find another subject that interests you for a
future assignment. And don't forget when on the internet you might be directed to
other printed books and articles that deal with your questions.
Above all have fun!!
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bailey1
Joined: 01 Jan 2010
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Posted: Jan 02, 2010 17:39 Post subject: Re: Seeking info on hyalite |
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Thanks guys.
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bailey1
Joined: 01 Jan 2010
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Posted: Jan 02, 2010 19:54 Post subject: Re: Seeking info on hyalite |
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Peter Megaw wrote: | BTW: Bailey's Mom, we hope you've learned a lot too...check out some of the other threads here, you might find some kindred spirits! Thanks for being there for her/him. |
Hello! Thank you for your feedback as well! I thanked Peter and others for their info. I am Bailey's Mother. The 200 High School kids were given an assignment to select one of 2000 Minerals to learn about and report on to their class members. The snow days provided additional days for the children to complete the assignment over the holidays. Bailey was working on the project while attending a family gathering. My brother, her uncle, suggested a forum...and that is how she entered your Mineral community. The answers provided gave us family members new things to talk about! This is an intriguing subject and I am glad that I have been enlighted on this subject. I have a new curiousity on Minerals, and my daughter has learned about her selected Mineral. She selected in randomly...I think she liked the name of it! It has led us on an interesting journey!
Thank you again, and Happy New Year.
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bailey1
Joined: 01 Jan 2010
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Location: virginia
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Posted: Jan 02, 2010 19:59 Post subject: Re: Seeking info on hyalite |
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Hello Peter! I am Bailey's Mother. I sent a reply and I am not sure if went to you.
Thanks to you and all the other individuals who replied to my daughter's questions.
As I stated in another email, my brother, her uncle, suggested a forum, since
she was having a challenging time locating information on her topic.
The descriptions of the origination of the Minerals, etc. led to some interesting
discussions in the family. Thank you again for opening our eyes to the world of Minerals!
There were 200 High School students who were asked to select from one of 2000 Minerals for a project. I know that many children have been learning a lot over the holidays!
Thank you and Happy New Year.
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bailey1
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Location: virginia
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Posted: Jan 02, 2010 20:04 Post subject: Re: Seeking info on hyalite |
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Hello! I am Bailey's Mother. Thank you again for all of the explanations to my daughter's questions! You helped to connect a lot of the dots!
Thanks again and Happy New Year.
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bailey1
Joined: 01 Jan 2010
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Location: virginia
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Posted: Jan 02, 2010 20:05 Post subject: Re: Seeking info on hyalite |
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Thank you for answering my daughter's questions.
Bailey's Mother
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Peter Megaw
Site Admin
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Posted: Jan 02, 2010 23:30 Post subject: Re: Seeking info on hyalite |
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Hello again Bailey, and your mom. I got your various messages, thanks! Once you start one of these threads it tends to take on a life of its own, so you and your mom might want to watch a bit longer to see who else chimes in. As promised here are a before and after shot of a typical hyalite specimen in normal daylihgt and under short-wave ultraviolet light.
I would certainly encourage you to keep studying minerals Bailey, there are not that many young people doing so, and even fewer young women (my daughter being an exception) which means it sets you apart from the hordes all trying to get in to the same schools...as well as being a source of life-long enjoyment and learning. If you happen to live somewhere near Arizona, I would encourage you to see if you can find a way to come to the Tucson Gem and Mineral Show in early February...an absolutely incredible annual temporary museum with exhibits from museums and private collectors worldwide. I suspect you can even find a nice hyalite specimen wihtout too much difficulty!
Description: |
Hyalite opal, Zacatecas, Mexico. minature...bubble is nearly 4 cm across. |
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Same specimen under Short-wave UV light |
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John S. White
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Posted: Jan 03, 2010 06:47 Post subject: Re: Seeking info on hyalite |
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So, Peter, why is it in your opinion that hyalite so often tends to contain enough uranium to make it fluoresce? This seems to be the case irrespective of the conditions under which it formed.
_________________ John S. White
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