Test For Transparent Glass Versus Rock Crystal Bottles..

[Wattana]

Great story Joey. And a good example of "low tech is best tech."

[Joey Silver / Si Zhouyi 義周司]

Giovanni,
 Thank you. 

Tom,
   Thank you too. As a general rule, I tend to agree. 
 But when it comes to health, I'll take the highest, newest, proven high tech I can get.   
Joey
 

[Mandarin]

Joey kindly taught me the 'bottle on cheek' way to determine if a bottle is glass or crystal, and on trying it on two bottles (one glass, one crystal) I immediately felt the difference between the two. The actual feeling is caused by the speed that heat from your cheek :O) is transferred to the bottle that is placed against it. So, although the temperatures of the two untouched bottles start off the same, when placed on your cheek they conduct heat at a different rate (they are said to have different thermal conductivity) and this is what the cheek test exploits. It is not a scientific test and is not always reliable, but it is a quick and easy comparative (if not absolute) method. The specific gravity test I think Tom mentioned is the easiest scientific method to perform. A mineralogist friend of mine also mentioned that glass will often have minute bubbles somewhere in its material that can be seen with a loupe.

Vaughan

[Fiveroosters aka clayandbrush]

Dear Vaughan,
that is exactly what I said.
Giovanni

[Joey Silver / Si Zhouyi 義周司]

Dear Vaughn,
   Ask your mineralogist friend if quartz can also have minute bubbles. I believe that I read somewhere (source unknown) that it can.
 George? Charll? Giovanni? Etc.?
Joey

[Fiveroosters aka clayandbrush]

Yes,
VERY rare but it can happen. At least I did read this on a mineralogist site times ago.
Giovanni

[Peter Bentley 彭达理]

Hi  All

Crystal  ( quartz)   vs  glass  :  how to  spot the  difference ?

I  recently   did  a  bit  of  research into  this  and  found  out that the   specific  gravity (density)  of glass and quartz  are  both  much the  same   :  about   2.4  -  2.8  gm/cc

BTW  :  check  this  amazing  link  into  natural  gemstones :  wonderful   what  nature  has   created  for  us !

GEORGE : Don't  drool !

http://www.gemselect.com/gem-info/specific-gravity.php

So  what  is  it  that   "naturally"  makes  us   feel  a  quartz  (rock  crystal)  bottle  is  a   quartz  bottle   and a    glass  bottle  is a  glass  bottle ? 

Is  it  really the  perceived  "density"  - meaning  the  weight of the  bottle  vs  its  size  ? 
Or  the   the  thermal  conductivity  (the  "cheek"  test) ?
Or the   scratch test ?

Of  course  natural  crystal  has  tiny  imperfections   which is  the  ultimate  give-away  vs man-made   crystal  which is   flawless.  ( I  do  happen  to  own  a   natural  rock crystal bottle  from the  mid  2000's  by Song Yiming  which came  with  an  original  gemologist   certificate - the   first  and  only time   that ever  happened) 

[I also  know  that one of the   top  "junior"  artists  in Hengshui  these  days ,  Da  Yong  =  Zhang  Yong    comes  from a  family which  specializes  in  natural  crystal   and  other   types  of  rare  stones. On  one   of my earliest  trips  to  Hengshui  a  fellow  guest  at  dinner  with  him  was  a  dealer  in  rare  stones  from  somewhere   in  S.E. China ( Jiangsu ? ) .   I did  not  realize the   significance  of  this  until  just  my last  trip to  Hengshui  when  Da  Yong  showed me  his latest   set of  bottles  - almost all  of  which were  painted  inside  special  types  of  quartz  and  other  varieties  of  minerals   e.g  agate .  I  finally  bought  a  totally    superb    abstract   landscape  bottle  which he  painted  inside a  very ( VERY)  thick natural , 99 %  flawless quartz  bottle * . He   asked  only  RMB 20K  which was a  pure  'friendship" price  because  I'm sure he  could  have  sold  it  within  China  for   twice  that .  But  he  told  me that  actual raw bottle  cost  him RMB 7-8 K , which  I  can  believe. ]   

I think that  it's  actually because  a  glass  bottle  can be (indeed  must be)   blown  and  is therefore  naturally  thin  and  light.

However, a  quartz  bottle (whether  natural  or  man-made)   must be  bored  out  from  within  from a  solid  block,  so the   bottle-maker  stops  well before   reaching the  outer  surface  and  breaking through,  thus   quartz  bottles  are  naturally    thicker  and  thus heavier   size-for-size

And of  course  being thicker  they  pass  the  "cheek"  test .

(Actually  the  thermal  conductivity  of  quartz  is  about  3   vs  about  1  for  glass so   if   given  two  exact  one-for-one  / thickness-for-thickness    bottles  :  glass   vs   quartz    the    quartz  bottle   would  feel   warmer to the  cheek than  the glass  bottle, not  colder) 

Any  comments ?

___________

Re  this   little   story  from the  past:

"This reminds me of a story about the Space Program. When Ilan Ramon z"l (the Israeli astronaut who was killed with all his US team-mates in space), was going to go up, NASA told the Israel Air Force (where Ramon was a pilot), that he'd need at least 2 pens which would write in space. They said they'd developed such a pen at a cost per pen of US$45,000, and would sell Israel the pens at cost. The government thanked them but refused. Ramon went into space with 12 pencils, at a total cost of US$6"

I  heard  an alternative  ( and  probably  more  true)  version:

 The  USA   developed a  special  ball-point  pen  for the  space  station  that  would  work in  zero  gravity  at the  cost  of   over  US$1  million ( and in fact there really   was a  commercial  version  that was  sold   about   30  years   ago   as  a gimmick, and  I  once  bought  one   -  as  if  one  would ever  want  to  write  upside  down !) .

The  Russians  used a  pencil !

____________________

Cheers

Peter

* The  background  to this  was   that  on my  last  trip  to  Hengshui   in May this  year ,  Da  Yong kept  appearing  in  almost every meal, no matter  which   special   circle  of  artists  were  involved as  long as they  were  "junior"  artists  i.e.   20s -  40s .  It  seems  he  is a  real   " (wolf) pack leader "  in Hengshui  and  I'm betting that  he's the   true   successor  to   WXS,   rather than  WZY.   I  kept  joking  with  him  that  "I  love  you  but  I  don't  love  what  you  paint"  because  Da  Yong  rarely paints  landscapes . So  on  the last  morning  in Hengshui  I  accepted  his  invitation   to  go  to  his  home  and  he showed  me  his  latest   creations.  In truth  out  a  couple of   dozen  bottles   50- 60 %  were  painted inside special   stone  bottles,  and  only  a   couple  were   Chinese  landscapes,  of  which  I  intermediately picked  on   the  best  IMHO   and   looked  at it  for  over  one  hour in various  lights  before  deciding  I  must buy it .
Inside-painted  bottle   collecting  is  addictive .....
Beware !   

[Wattana]

   

I think that  it's  actually because  a  glass  bottle  can be (indeed  must be)   blown  and  is therefore  naturally  thin  and  light.

However, a  quartz  bottle (whether  natural  or  man-made)   must be  bored  out  from  within  from a  solid  block,  so the   bottle-maker  stops  well before   reaching the  outer  surface  and  breaking through,  thus   quartz  bottles  are  naturally    thicker  and  thus heavier   size-for-size

And of  course  being thicker  they  pass  the  "cheek"  test .

(Actually  the  thermal  conductivity  of  quartz  is  about  3   vs  about  1  for  glass so   if   given  two  exact  one-for-one  / thickness-for-thickness    bottles  :  glass   vs   quartz    the    quartz  bottle   would  feel   warmer to the  cheek than  the glass  bottle, not  colder) 

Any  comments ?

Hi Peter,

Yes, two comments:

(1) Many older and finer glass bottles are not blown, but hewn out of a solid slab of glass, in exactly the same way as a natural quartz bottle.

(2) Relative thermal conductivity - are you saying that glass is three times better at conducting heat than quartz? I find that hard to fathom. OK, I understand what you are saying about the thinness of a blown glass bottle vs. a thicker hewn quartz bottle. But if you place two solid slabs side by side at room temperature, one glass the other quartz, I believe you will sense the quartz block to be colder to the touch than the glass one (e.g. the cheek test). 

Thanks for sharing your experiences of the IP artists' social scene.

BTW, I just tried the gem link you gave and got this message on my screen:

We apologize but our service is not available in your area.

I wonder why Thailand would block this site? To protect the fake gem business...?   

Tom

[Peter Bentley 彭达理]

Hi  Tom

1)  Yes  many  older  glass bottles  were  blown , of  course,  (which  may  explain  why they later  cracked )

    Entering  into  virgin  territory  on this  matter,  which  is   strictly  off  my  limits

Hence  often  the  provenance   on the  bottle  itself is   quoted  as  well  as  the  artist  (  see  some   early  WXS  bottles , for   example,  when  WXS   could   only   use   pre-painted  bottles   from the  19th  C  )*

2) Just  the opposite :  Glass  =  TC  1   and   Quartz =  3  . 

 If  I read   thermal  conductivity   data  correctly quartz   should  pass  heat  faster  than  glass ,  which  would fail the  "cheek"  test   .  3  >  1  !

Anyway....

Cheers

Peter

PS:  Re  the  blocked  site  :  I  just  did  a  simple  google  on   "specific  gravity -  stones "   and   came  up with that   amazing   website ,  complete  with  pics  of  stones.   I  cannot  imagine   why  Thialand  would  block  such a  simple   site.   Try  another  google  yourself....

[Wattana]

Hi Peter,

Re. thermal conductivity - if, as you say, heat passes through quartz FASTER than glass, it would give the quartz a COOLER sensation. Puzzle solved!

Re. blocked website - I just tried that - a fresh Google search using the phrase you suggested. Same result! And, in VERY SMALL PALE GREY print at the bottom of the screen are the words:

SETT Co. Ltd. - Southeast Thailand Trading Gold & Gems

It is clearly a Thai-based website, and they DO NOT want Thai viewers looking at it, for reasons that escape me! 

All best,
Tom

[Peter Bentley 彭达理]

Hi  Tom

WRONG !

High  thermal   conductivity   would  mean  a  "warm"  feeling , not a   cool feeling  ( =  thermal  equilibrium)

Actually   glass     whether  real  glass   or     real  quartz  or   whatever    thickness  must  be  the  key    because   heat  transmits  so  slowly  regardless  of  thermal  conductivity

Thickness  of  the  medium  is  the  key

Cheers

Peter

[Fiveroosters aka clayandbrush]

Dear Peter,
sorry but you are totally wrong. Please read carefully, it is extremely simple.
Temperature is energy. If one object is warmer than another one, it means that it is retaining a bigger quantity of thermal energy. That energy tends naturally to reach an equilibrium, so if you put those two objects in contact, the one with more energy (the warmer one) will transfer part of his energy to the coldest one. How much energy, and for how long? Until they reach the exact same temperature, or state of thermal equilibrium. This happens anyway, not only by direct contact, but also by radiated energy or by transferred energy through the air, it is just matter of time. This means that if you put three objects of different material in the same room, they all will reach the same temperature, the same exact temperature, given the proper time for that.
Now, suppose that the three objects are a glass 1 mm thick, a glass ten time thicker, 10 mm, and a piece of wood. The glass has a thermal conductivity which is much higher than the wood, mainly because it is a much more compact material. Now, you take the thin glass and you put it in contact with your cheek. What happens when you do that?  It happens that you have put in contact two objects of different temperature, one being the glass which is at room temperature, i.e. let say 20 degrees Celsius, and the other one being your cheek, i.e. about 37 degrees Celsius or more if you have fever. Then part of the temperature of your cheek starts to be transferred to the glass. So the temperature of the part of your skin that is in contact with the glass starts to become cooler because part of his own thermal energy is transferred to the glass. The temperature sensors on your skin surface, which were sensing the surface temperature of your skin, now are practically sensing the temperature of the glass, which is cooler than you. Now you take off the glass and put the wood against your cheek. It has the same exact temperature of the glass, but how do you feel it? Cooler than the glass? On the opposite, you feel it much less cooler because his thermal conductivity is lower than that of glass. Your cheek is transferring temperature to it at a much slower speed, so the temperature of your skin does not decrease so suddenly as it happened with glass. In practice, you feel it warmer than glass although both them were at the same exact temperature. Result of this first test: A MATERIAL WITH HIGHER THERMAL CONDUCTIVITY IS SENSED COOLER BY OUR CHEEK. That is clear, so if rock crystal has an higher thermal conductivity than glass, it is felt cooler by us, no doubt.
Now, about thickness. When you put in contact the 1 mm thick glass or the 10 mm thick glass with your cheek, at the very beginning the heat is transferred to them with the same exact speed, so you feel them exactly the same. What happens is that the 1 mm thick glass is 10 times lighter than the other one, it has a much lower mass to be heated so its temperature increases faster than the thicker one. This gives you the impression that it is warmer but it isn’t, it is only matter of heating speed. One can think that thickness is the key, but it is a false interpretation. The key there is mass. The speed of temperature transfer is the same, the only difference is that you have to transfer much more QUANTITY of energy to the thicker one. It is the same than boiling 1 liter of water or 10 liters of water. It is all the same except the different quantity, which takes more time. SO HEAT IS TRANSFERRED AT DIFFERENT SPEEDS DEPENDING ON THERMAL CONDUCTIVITY, REGARDLESS THICKNESS.
Tom is right that we should avoid posting the same post in two different threads, because now I have to post this comment too on both them to avoid false interpretations. It is much better to use links.
Kind regards
Giovanni

[Peter Bentley 彭达理]

Hi Giovanni

Now  this is getting  into  very  serious   Physics, at  which  I  have  not  only  a   1st  Class  Oxford  degree ,    but  also a  D. Phil  (in  low  temperature   physics  engineering )

Truth !

The   question is :  does  the  "cheek  test  work"   Yes  or  no ?

Frankly  I  don't  know        

I have  never   done  the  test   in a   scientifically    set  up   program, and that's  the only  way  to   set a  standard  for  tests

So the    whole   question is  open  !

As  to  specific  gravity ( density),  thermal  conductivity    etc  -  these are  established    facts

 

As  to the  amount  of  good  Italian wine  needed   to  interpret  the  facts   from  the  myth  that's a    fact  which needs  a  lot  of good   wine  to  interpret  .....

Challenge  you !

    

Cheers

Peter

PS :  Thermal  conductivity   is  a  very   tricky  thing...   I  bridged  the  gap  between     liquid helium  ( 4  degree  Kelvin  =  4  degree  above  absolute  zero )   and   room  temperature    with a  few  PTFE  spacers )

[Wattana]

Re. thermal conductivity - if......heat passes through quartz FASTER than glass, it would give the quartz a COOLER sensation. Puzzle solved!

Thank you dear Giovanni,

You have validated my earlier statement!

Tom

PS: But on second thoughts, I prefer the idea of reviewing the 'facts' over a bottle of Italian wine... 

[Peter Bentley 彭达理]

Hi  All

Seems  Tom and  I  agree

Italian  wine  is  the   essential  ingredient !

 

Cheers

Peter

PS :  also   temperature   and  good  Italian   food  can  somehow  change  a   mediocre    B----   Italian wine  in to  an  AAA +++  class   wine!


 Magic !

[Wattana]

And I believe the Italian wine conductivity test is very simple and effective.

After the 'cheek test' one proceeds directly to the 'inside of my throat' test....which may take several hours to complete.     

Tom

[Peter Bentley 彭达理]

Tom !

Do you mean  'deep  throat '  b?

If  so  that's  off  limits  ( at least on this  forum)

 

Cheers

Peter

[Fiveroosters aka clayandbrush]

Dear Peter,
sorry, I can’t believe at what I am reading:
“Now  this is getting  into  very  serious   Physics”: I don’t agree, that is very elemental and anyone, if does not already knows that, can perfectly understand it by reading carefully what I wrote.
“I  have  not  only  a   1st  Class  Oxford  degree ,   but  also a  D. Phil  (in  low  temperature   physics  engineering )”: no comment.
“The   question is :  does  the  "cheek  test  work"   Yes  or  no ?”: try what I did suggest, touch a piece of glass and a piece of wood with your cheek: does it work or not? Come on!
  “I have  never   done  the  test   in a   scientifically    set  up   program, and that's  the only  way  to   set a  standard  for  tests”: it is not necessary, see previous answer, but if you wish, place a thermocouple on a heated block of iron (correspond to your cheek) and a thermocouple on each of the three objects and put them in contact. You will see that the temperature of the 1 mm thin glass will increase quickly, the temperature of the 1 cm thick glass will increase slowly and the temperature of the wood will increase extremely slow. It is so obvious that it is not necessary to perform the test.
“So the    whole   question is  open  !”: sorry but to me it is closed.
“As  to  specific  gravity ( density),  thermal  conductivity    etc  -  these are  established    facts”: exactly, and they works as I said, not in the opposite way.
A further note: you seems not to agree on the clear reasoning that I made, but you have not exposed any reasoning against that, supporting if what I have said is wrong. Can you do that? Frankly not, because what I said are not sensations, but facts that can be perfectly proved, both scientifically and empirically.
Dear Peter, all this for love of truth, because if someone read what you did write, i.e. that thermal conductivity works on the opposite way, and that the heat transfer rate depends from thickness and not from thermal conductivity, will have a distorted vision of reality.
Kind regards
Giovanni

[Peter Bentley 彭达理]

Hi Giovanni et   al

 


1. Sincere   apologies  to  enter   such  a    deep debate   where I   am  clearly   NOT   qualified

2.  See  point  no 1

3. Re  thermal  conductivity    - as  sensed  versus   as measured  :  it's  one  of  those  things  like  the age   of  the   Universe  :  13.8   or   13.9  billion years  ?

4.  See point  1  ( or  point  4)


Very  seriously  :  although  a   very  long-term    Forum   contributor  ( you can  check me   on the "member"    list  -   go  the  top  bar   headings)   I  actually  know   ZERO  outside  VMIPBs

Yours   humbly

Peter

PS:   But  I do  enjoy  good  jokes !

[YT]

Dear Peter, Giovanni and Tom,

The opinions and viewpoints set out by the 3 of you have great appreciation from myself. It gives me greater understanding of crystal, quartz and glass but with a more fun(unbiased) way.

Thank you guys

Cheers,
YT