Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: How do you know it's silver?

Learn more physics!

Most recent answer: 03/04/2013
Q:
what is a good way to tell if something is silver? i found a couple of rings years ago and was just wondering how i can tell if there gold,white gold or silver.Is there a way to tell without taking it to a jeweler or gold and silver shop?thank you travis i also did not see any marks on the pieces.a friend told me that there should be marking to show its real?
- Travis Forrest (age 23)
high ridge missouri
A:
If the ring is attracted by a magnet it's not silver.  Another way to see if it's pure silver is to measure its density.  Archimedes figured this out a long time ago when King Hieron II of Syracuse asked him to determine if his crown was made of pure gold.  (It wasn't). What you do is to carefully weigh the object and then determine its volume by seeing how much water it displaces when immersed.  Easier said than done if you are not careful.  Dividing one by the other gives you the density.   For silver you should get about 10.5.   For brass, a common dilutent of silver and gold the density is around 8.
Gold is pretty heavy, 19.5 or so. So somebody clever could make an alloy that's got the same density as silver, although that would require care.

Another sure-fire way is to take it to your local jeweler.

LeeH

One way to test whether the surface is silver is to see if it tarnishes when exposed to sulfur compounds. There are various suggestions (untested by us) on websites for how to do this using mustard, matches, etc. That won't tell you about the inside material, however. Mike W.

(published on 08/20/2011)

Follow-Up #1: Is my silverware silver?

Q:
how can you tell if your silverware is silver
- jason (age 40)
oneida ny madision
A:

There are a number of was to test if something is silver or not. One easy to test property is the density of your silverware. Weigh your silverware and then put the silverware in a container that is filled to the brim with water. Carefully capture all the water that overflows and then weigh this water. If it is real silver, the ratio of (weight of water/weight of silverware) should be around 10.5 because silver is around 10.5 times as dense as water.

 In fact, this about the same as Archimedes' "Eureka" moment where Archimedes discovered a way to test if a gold crown was pure gold or had some silver in it and was so excited he jumped out of his bath and ran around town yelling "Eureka!" while naked. While the technology of the day would not have been advanced enough for Archimedes to do the procedure described above, what he could do is see if the volume of the "gold" crown was the same as that of pure gold of the same mass by immersing a balance of the crown and gold in water. Because the crown had some silver (which is less dense than gold) the volume of the crown and the buoyant force was larger and so the crown weighed less in water than an equivalent amount of gold. The king thanked Archimedes and the stealing goldsmith was killed.

Additionally, silver will tarnish when exposed to the air and especially when exposed to sulfur, which you can find in mustard (which can be cleaned off with a weak vinegar and baking soda solution or a weak acid solution).

I hope this helps!

Erik


(published on 03/04/2013)

Follow-up on this answer.