Why is platinum heavier than gold when used to make a ring?
- Thread starter abefroman
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Engagement Ring Expert
Rough_Rock
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In addition to platinum''s superior density, platinum jewelry has greater purity of the metal--i.e., most platinum jewelry is made with 90% platinum and 10% iridium, also a metal in the platinum family, and so you have more of the more precious metal.
24 karat gold is pure, so 18 karat gold is 18/24 pure, or 75% pure gold. The remaining 25% is a mixture of alloys, typically including copper for yellow gold and nickel for white gold. So in essence nickels and pennies are going into your ring. Since gold is yellow in nature, white gold is not natural, and eventually, the yellow hue begins to shine through white gold jewelry. As a result, white gold rings often require white gold plating--nickel or rhodium--in order to maintain a white appearance.
With platinum, a pure white precious metal, you can literally feel the luxury and your center diamond will appreciate it because platinum prongs take much longer to wear out than gold prongs--i.e., because gold is less dense and in jewelry less pure, gold prongs wear out faster and often need retipping.
Back in the 1980''s, women wore tennis bracelets made famous by Chris Evert Lloyd who dropped one on a tennis court. Well, the reason it fell, and the reason tennis bracelets quickly fell out of vogue, is because they were made of gold and the links wore out very quickly. Had the bracelets been made of platinum, they would have been heavier but they also would have lasted much longer. For this reason, platinum is the metal of choice for royalty because their intent is to pass on the piece for generations to come.
If you plan on having your marriage last till death to you part, it makes sense to invest in the finest quality materials so that your engagement ring and wedding band will be there for you not just in your golden years but well into your platinum years. The last thing you need is to have your diamond come lose, fall out or be subjected to additional wear and tear because you chose to set this precious gem into a weaker metal. Four solid platinum prongs are stronger than 6 white gold prongs, so you don''t have to cover up your entire diamond just to add extra security when you go with platinum. You can expose the beauty of the curves of your diamond, and any laser inscriptions on branded diamonds, without compromising strength and security.
24 karat gold is pure, so 18 karat gold is 18/24 pure, or 75% pure gold. The remaining 25% is a mixture of alloys, typically including copper for yellow gold and nickel for white gold. So in essence nickels and pennies are going into your ring. Since gold is yellow in nature, white gold is not natural, and eventually, the yellow hue begins to shine through white gold jewelry. As a result, white gold rings often require white gold plating--nickel or rhodium--in order to maintain a white appearance.
With platinum, a pure white precious metal, you can literally feel the luxury and your center diamond will appreciate it because platinum prongs take much longer to wear out than gold prongs--i.e., because gold is less dense and in jewelry less pure, gold prongs wear out faster and often need retipping.
Back in the 1980''s, women wore tennis bracelets made famous by Chris Evert Lloyd who dropped one on a tennis court. Well, the reason it fell, and the reason tennis bracelets quickly fell out of vogue, is because they were made of gold and the links wore out very quickly. Had the bracelets been made of platinum, they would have been heavier but they also would have lasted much longer. For this reason, platinum is the metal of choice for royalty because their intent is to pass on the piece for generations to come.
If you plan on having your marriage last till death to you part, it makes sense to invest in the finest quality materials so that your engagement ring and wedding band will be there for you not just in your golden years but well into your platinum years. The last thing you need is to have your diamond come lose, fall out or be subjected to additional wear and tear because you chose to set this precious gem into a weaker metal. Four solid platinum prongs are stronger than 6 white gold prongs, so you don''t have to cover up your entire diamond just to add extra security when you go with platinum. You can expose the beauty of the curves of your diamond, and any laser inscriptions on branded diamonds, without compromising strength and security.
First I want to correct my definition of atomic weight from before (which was wrong, and therefore probably just caused more confusion).. Atomic weight is the ratio of the average mass per atom of the element to 1/12 of the mass of an atom of 12C. (Geez..you''d think I would have remembered more from school!)
I''m going to think through your above post this evening and get back to you then. Thanks for making me think Abe!
It seems like the parameter of atomic radius is not as ''cut and dry'' as the radius of a solid would be.
I''m thinking that your answer lies in the electron configuration of the two outer shells of gold vs. platinum and how the atoms join together. This is me trying to reach way back to the two chem courses I had to take as an undergrad, but here it goes..
platinum outer shell = 1 electron
platinum next to outer shell = 17 electrons
gold outer shell = 1 electron
gold next to outer shell = 18 electrons
Maybe since the gold ''next to outer shell'' is full with 18 electrons, then the atoms would join only in the outer shell and with platinum you would have overlap of electrons in the two outer shells (packing them more tightly together) so that the two outer Pt shells will be full and therefore more stable?
I don''t know if that''s correct..just a guess. I''m no chemist. If we have any PS chemists, please chime in! I''m curious now too!
I''m thinking that your answer lies in the electron configuration of the two outer shells of gold vs. platinum and how the atoms join together. This is me trying to reach way back to the two chem courses I had to take as an undergrad, but here it goes..
platinum outer shell = 1 electron
platinum next to outer shell = 17 electrons
gold outer shell = 1 electron
gold next to outer shell = 18 electrons
Maybe since the gold ''next to outer shell'' is full with 18 electrons, then the atoms would join only in the outer shell and with platinum you would have overlap of electrons in the two outer shells (packing them more tightly together) so that the two outer Pt shells will be full and therefore more stable?
I don''t know if that''s correct..just a guess. I''m no chemist. If we have any PS chemists, please chime in! I''m curious now too!
I''m going to take one more crack at this.. 
From what I could read quickly (without re-teaching myself chemistry), in simple terms, sometimes an element with a higher atomic mass can have a lower density because of how closely packed the atoms are. So, in our case, it appears that although gold has a higher atomic mass, the platinum atoms are packed closer together than the gold atoms, causing platinum to have a higher density.
I''m not sure if the Platinum atoms are packed closer together because of my guess about electron configuration in the last post, but from what I''ve read I think so. I''d love to know the answer for certain though, so if there are any Chemists out there, I''d love your input!
To address your question on atomic radius (again, with my very simple understanding), the atomic radius is the distance from the nucleus to the outside of the electron cloud in a single atom. Since this distance is not always the same, I believe that the atomic radius is an approximation. When you have molecules (more than one atom joined together), the electron clouds overlap between atoms. So, it''s not the same as picturing two buckets with the same volume with different sized balls in them.
Hope this helps!
From what I could read quickly (without re-teaching myself chemistry), in simple terms, sometimes an element with a higher atomic mass can have a lower density because of how closely packed the atoms are. So, in our case, it appears that although gold has a higher atomic mass, the platinum atoms are packed closer together than the gold atoms, causing platinum to have a higher density.
I''m not sure if the Platinum atoms are packed closer together because of my guess about electron configuration in the last post, but from what I''ve read I think so. I''d love to know the answer for certain though, so if there are any Chemists out there, I''d love your input!
To address your question on atomic radius (again, with my very simple understanding), the atomic radius is the distance from the nucleus to the outside of the electron cloud in a single atom. Since this distance is not always the same, I believe that the atomic radius is an approximation. When you have molecules (more than one atom joined together), the electron clouds overlap between atoms. So, it''s not the same as picturing two buckets with the same volume with different sized balls in them.
Hope this helps!
Date: 8/25/2009 5:32:57 PM
Author: nclrgirl
I''m going to take one more crack at this..
From what I could read quickly (without re-teaching myself chemistry), in simple terms, sometimes an element with a higher atomic mass can have a lower density because of how closely packed the atoms are. So, in our case, it appears that although gold has a higher atomic mass, the platinum atoms are packed closer together than the gold atoms, causing platinum to have a higher density.
I''m not sure if the Platinum atoms are packed closer together because of my guess about electron configuration in the last post, but from what I''ve read I think so. I''d love to know the answer for certain though, so if there are any Chemists out there, I''d love your input!
To address your question on atomic radius (again, with my very simple understanding), the atomic radius is the distance from the nucleus to the outside of the electron cloud in a single atom. Since this distance is not always the same, I believe that the atomic radius is an approximation. When you have molecules (more than one atom joined together), the electron clouds overlap between atoms. So, it''s not the same as picturing two buckets with the same volume with different sized balls in them.
Hope this helps!
Thanks! I think your right.
GossamerAngel
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cindygenit
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Oooh chemistry question!
Platinum is denser than gold.
white gold is alloyed with less dense metals such as silver. Therefore, an 18 k white gold wing will be less dense than a 24 k WG ring of the same size or a platinum ring of the same size.
Someone has already pointed out that 18K WG is only 75% gold, whle platinum is 95% pure platinum.
Platinum is denser than gold.
white gold is alloyed with less dense metals such as silver. Therefore, an 18 k white gold wing will be less dense than a 24 k WG ring of the same size or a platinum ring of the same size.
Someone has already pointed out that 18K WG is only 75% gold, whle platinum is 95% pure platinum.
ChemGeek
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Oh this is right up my alley!! I don''t work with metals, and haven''t studied them in a while, but I''ll give this a shot since I haven''t worked with densities, periodic tables, etc...since undergrad (I work in pharma now...much different!) and my gen. chem book is actually out in my car right now... but I''ll see what I can come up with. Most of what has been said already is right on, though.
Density of Platinum = 21400 kg/m^3 (21.4g/cm^3)
Density of pure gold = 19320 kg/m^3 (19.32 g/cm^3) (random FYI: a sqare foot of gold weighs over a thousand pounds!)
And yes, the more pure it is, the heavier it is, so since gold is usually some sort of alloy, so depending on what other metal and how much is mixed with the gold, this can make it much lighter than a platinum alloy.
Then you have the electron oribitals (which have also already been mentioned) and yup, each has one valence electron, and there is also metallic bonding which gives metals their unique properties of malleability and conductivity. Metallic bonding is caused by the electromagnetic interaction between delocalized electrons.
That''s about all I can say without getting overly complicated and getting into some stuff that even I have no clue about (physical chemistry and quantum mechanics...AAAACK!!!
)
So yeah, it all boils down basically to how pure it is, and how closely packed the atoms can be in a given element.
Density of Platinum = 21400 kg/m^3 (21.4g/cm^3)
Density of pure gold = 19320 kg/m^3 (19.32 g/cm^3) (random FYI: a sqare foot of gold weighs over a thousand pounds!)
And yes, the more pure it is, the heavier it is, so since gold is usually some sort of alloy, so depending on what other metal and how much is mixed with the gold, this can make it much lighter than a platinum alloy.
Then you have the electron oribitals (which have also already been mentioned) and yup, each has one valence electron, and there is also metallic bonding which gives metals their unique properties of malleability and conductivity. Metallic bonding is caused by the electromagnetic interaction between delocalized electrons.
That''s about all I can say without getting overly complicated and getting into some stuff that even I have no clue about (physical chemistry and quantum mechanics...AAAACK!!!
So yeah, it all boils down basically to how pure it is, and how closely packed the atoms can be in a given element.
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Pure gold has a weight of 19320 KG /Cubic meter. Pure platinum has a weight of 21400 KG/ cubic meter. Platinum has a greater specific gravity than Gold.
When metals are alloyed, they are mixed by WEIGHT with nearly always less costly and lighter specific gravity metals. There are a few minor exceptions. The result is that 14 or even 18 karat gold is far liighter than 90% platinum. There is a lot more, by volume, light weight alloy in 14 karat and 18 karat gold than the lighter weight alloy added to platinum.
14 karat gold is about 58.5% gold BY WEIGHT, but if one looked at the VOLUME of the alloy used, one would find more volume of alloy is used in 14 karat than the volume of gold. By volume, 14 karat gold is less than 50% pure gold...... Kind of tricky. Karat content is based on a relaitonship of weight without regard to volume.
When metals are alloyed, they are mixed by WEIGHT with nearly always less costly and lighter specific gravity metals. There are a few minor exceptions. The result is that 14 or even 18 karat gold is far liighter than 90% platinum. There is a lot more, by volume, light weight alloy in 14 karat and 18 karat gold than the lighter weight alloy added to platinum.
14 karat gold is about 58.5% gold BY WEIGHT, but if one looked at the VOLUME of the alloy used, one would find more volume of alloy is used in 14 karat than the volume of gold. By volume, 14 karat gold is less than 50% pure gold...... Kind of tricky. Karat content is based on a relaitonship of weight without regard to volume.
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Using the data we had above I have a bit of a brain twister for you. The math whiz's will not have a problem, but it is a fun way to look at the facts.
Take 58.5% of a cubic meter of gold. It would weigh 11302kg. Now, if you wanted to use the typical mostly copper and a bit of silver alloy to make it 14kt, you would be using metals with an average, round number, kg/cu.m of about 9300. By the time you put in enough alloy to make the gold into 14 karat you would have 1.447 cubic meters of material. The alloy is mixed in by weight and not by volume as I have indicated previously, but what most people think about is how cooking recipes depend on volume measures, such as cups and tablespoons while gold and platinum are cooked up by weight relationships. You actually come out with 14 karat being closer to 40% by volume.......
Take 58.5% of a cubic meter of gold. It would weigh 11302kg. Now, if you wanted to use the typical mostly copper and a bit of silver alloy to make it 14kt, you would be using metals with an average, round number, kg/cu.m of about 9300. By the time you put in enough alloy to make the gold into 14 karat you would have 1.447 cubic meters of material. The alloy is mixed in by weight and not by volume as I have indicated previously, but what most people think about is how cooking recipes depend on volume measures, such as cups and tablespoons while gold and platinum are cooked up by weight relationships. You actually come out with 14 karat being closer to 40% by volume.......
ChemGeek
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