johnk
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Help with crystals of boric acid - challenge
Hello,
I know this is a long shot, but please view the photo of the flakes, boric acid, has anyone ever crystallized/created/modified boric like this? If so
, I need help! I want to achieve this result.
Thanks
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elementcollector1
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http://www.scienceforums.net/topic/63966-boric-acid-help-ple...
This might help.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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12AX7
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Seems to me a fluffy, flaky texture is typical. Don't think I ever got crystals that big (unless it's very zoomed in), but the flaky appearance is
right. Similar to PbCl2.
Tim
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johnk
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Thanks already checked other forums, not much help,
As for "Tim" what was your method? Flake size can probably vary depending on rate of cooling, but I haven't been able to get the flaky, slippery,
layered structure? Mine is granular, it looks vitreous but once touched just disappears.
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johnk
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no ideas anybody? how to change/modify appearance of boric acid?
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Morgan
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I was reading that "boric acid is obtained in beautiful lustrous scales from a native calcium borate found in California." There's a simple experiment
where you heat boric acid in a spoon and drive off the water. The viscous liquid remaining when touched with a glass rod or stick will form long
threads that can be drawn off. "If the fused mass in the spoon is allowed to cool, it will contract and crack in every direction."
Alfred Morgan "Simple Chemical Experiments"
On a somewhat related note, I think it would be fun to grow ulexite crystals if you could make them as good as some specimens.
"Ulexite (NaCaB5O6(OH)6•5(H2O)) (hydrated sodium calcium borate hydroxide), sometimes known as TV rock, is a mineral occurring in silky white
rounded crystalline masses or in parallel fibers."
http://en.wikipedia.org/wiki/Ulexite
http://books.google.com/books?id=rFX6WyvVlHwC&pg=PA956&a...
I have a chunk of ulexite and if you haven't seen it, it's not like looking through glass but more as if it lifts the image to the surface of the
rock, which is kind of hard to see in a video but the effect is quite striking if holding it in your hand.
http://www.youtube.com/watch?v=isPBecyaZYg
Here's a photo I took of my piece of ulexite. It used to have a nice smooth surface but it has aged/fogged or become scuffed up somehow.
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watson.fawkes
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Quote: Originally posted by Morgan  | | Here's a photo I took of my piece of ulexite. It used to have a nice smooth surface but it has aged/fogged or become scuffed up somehow.
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Since ulexite is an evaporite mineral, it's likely fogged up through ambient humidity. If you repolish it,
store it in a little ad hoc desiccator box to keep its surface fresh.
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Morgan
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Another thing to try besides making "beautiful lustrous scales" would be to draw out lots of long fibers of melted boric acid and bundle/manufacture
them into a kind of fiber optic pseudo-ulexite mass while they are still sticky. I wonder if boric acid fibers would produce the same coherent "TV"
effect with an equal light transmission?
Here's a funny little ring that seems a creative use of ulexite.
http://www.gaalgyongyver.hu/gal_gy_14_en.html
Another product.
http://www.greatsouth.net/minerals/p-M605.html
"When ulexite has a fibrous habit, it forms in a lot of long, thin, cylindrical strands. The strands are packed closely together like a fiber optic
bundle. If you cut the rock perpendicular to the strands, you would see a group of circular cross-sections packed very closely together. Still there
is space between the strands that is filled with either water or air, which has a lower index of refraction. The circular section and the differences
in index of refraction cause light that enters the fibers to be internally reflected. Thus, light enters from a variety of angles, but comes back up
the strands bringing the image with it."
http://www.uhh.hawaii.edu/~kenhon/mineralogy/course-syllabus...
[Edited on 4-11-2012 by Morgan]
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Morgan
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| Quote: Originally posted by watson.fawkes | | Quote: Originally posted by Morgan | | Here's a photo I took of my piece of ulexite. It used to have a nice smooth surface but it has aged/fogged or become scuffed up somehow.
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Since ulexite is an evaporite mineral, it's likely fogged up through ambient humidity. If you repolish it,
store it in a little ad hoc desiccator box to keep its surface fresh. |
Some tidbit from the last paragraph, pdf page 11. Strange with all their work they haven't made a conclusion here.
"We have not investigated another curious observation
about ulexite single crystals. Murdoch (1940)
and R. C. Erd, U.S.G.S. (personal communication)
note that some clear single crystals of ulexite remain
clear as long as they are stored with others but, when
isolated, appear to alter. Is there a loss of water, an actual
alteration to probertite, or decomposition?"
http://www.minsocam.org/ammin/AM63/AM63_160.pdf
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johnk
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Thanks so much for the replies and help, I am going to look at all the info, but what's really important for me is to actually form it into the
appearance as the photo, lustrous/vitreous flakes. Any detailed ideas about this? Thanks!
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Morgan
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One way to get "lustrous flaky crystals" ...
http://books.google.com/books?id=D6vQAAAAMAAJ&pg=PA180&a...
Tidbit
"Boric acid refers to 3 compounds; orthoboric acid (also called boracic acid, H3BO3 or B2O3·3H2O), metaboric acid (HBO2 or B2O3·H2O), and tetraboric
acid (also called pyroboric, H4B4O7 or B2O3·H2O). Orthoboric acid dehydrates to form metaboric acid and tetraboric acid above 170 C and 300C
respectively. Orthoboric acid is derived from boric oxide in the form of white, triclinic crystals. It is poorly soluble in cold water but dissolves
readily in hot water, in alcohol and glycerine. Metaboric acid is a white, cubic crystalls. It is soluble in water slightly. Tetraboric acid is a
white solid soluble in water. When tetraboric and metaboric acid are dissolved, it reverts to orthoboric acid. The main uses of boric acid is to make
borate salts such as borax and other boron compounds."
http://www.chemicalland21.com/industrialchem/inorganic/BORAX...
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Morgan
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Perhaps boric acid made by way of borax and sulfuric acid produces pearly flakes by having traces of sulphates. "P. Charles found two kinds of boric
acid in French pharmacies, ..."
"If the flaky acid be crystallized from a solution containing chloride or hydrochloric acid, it will separate in the form of prisms." (page 878)
http://books.google.com/books?id=nm8CAAAAYAAJ&pg=PA878&a...
Tidbits of possible interest
http://snovi.en.alibaba.com/product/600939909-0/Flaky_Boric_...
http://www.mondialtr.com/index27882.html?go=categoryDetail&a...
"We have found that the reduction of the growth rate of boric acid by sodium sulfate could be due to that salt competes with boric acid for the
adsorption sites on the crystal surface."
http://www.aidic.it/isic18/webpapers/272Alavia.pdf
[Edited on 6-11-2012 by Morgan]
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Morgan
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The plot thickens ...
"The flakes as seen in photo came into my possession from a client who requires boric acid flakes just like those."
http://www.chemicalforums.com/index.php?topic=56151.0
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Morgan
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Some good ulexite photos here.
"Collectors find the acicular form of Ulexite to be the most attractive, but most are not even aware that it exists. The very thin radiating needles
of Ulexite are very delicate and great care must be taken to protect them from damage. They are found growing in cavities in the ore, sometimes
growing on sparkling white or tan Colemanite crystals. They can make stunning specimens, but great care must be taken in collecting and storing them."
"The old timers would talk about the big foot long pieces of TV rock that they once had or saw, but 50 years of experience have taught me that these
were just stories and that there was never such thing as a foot long piece of optical Ulexite. Most of this compact form of Ulexite is found mixed
with mud that prevents light being transmitted very far or that although the rough material looks like it might produce fine optical material, when
you cut and polish it, you find that the fibers are really not very parallel after all and that also limits the length of optical transmission."
http://www.mindat.org/forum.php?read,87,143167,258795
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