$34per oz
A Guide Book of United States Coins 2007 states "No [dollar] coins were made for circulation from 1981 to 1998." That doesn't mean proofs and sets weren't made then. So that is all I know. And I could also be wrong. :)
It depends greatly on the year, early silver dollar proof dollars can be worth several thousand dollars, modern silver dollar proofs of common dates might be worth $20 or so for silver scrap.
Half dollars dated 1964 and earlier are 90% silver and are worth about $11 in silver content. Keep in mind that proof, error, and key date coins may be worth much more than pure silver content. And from 1965-1970 the half dollar was 40% silver and is worth about $4.50 in silver content. Half dollars dated 1971 and later are not silver unless found in a US mint silver proof set. Note that any half dollar made during 1965-69 is only partially silver and is worth about $3. Halves dated 1971 and later contain NO silver and are only worth 50 cents.
silver
As of July 2009, nearly $153.68.
This coin 2010 is worth between .45-50.00
Johnson Matthey was created in 1817.
Johnson Matthey's population is 2,012.
It's just a ounce silver bar. Check the web site. A single bar is currently selling for $29.48.
Silver bars can be bought in different sizes. the Johnson Matthey silver bar weighs 1000 ounces. There are some that weigh only 10 ounces.
Johnson Matthey is a chemical company that offers several different chemicals and products to its customers all over the world. They offer medical device components, metal joining, colours and coatings, and many more.
$34per oz
Peter Matthey's birth name is Peter James Matthey.
Francis Matthey was born in 1942.
Post new question with the date of the coin.
Johnson Matthey produced 5 gram fractional silver bars up until the mid to late 1980s, they are no longer made by JM, most of these bar were melted, so they are rather rare. Obviously 5 grams of 999 silver is worth its actual silver content based upon the spot price of silver, however many collectors seek out these bars so the value is substantially higher than the silver content, and typically these bars command a premium which well exceeds the spot price. Current market prices on JM 5 gram silver bars as of this writing are in the $40-$67 range depending on the institution offering them, sales by private parties are also a factor as these sales are generally from collectors who know the premium set upon them, these sales typically command the higher end of the scale. Also another factor on the value are how many bars happen to hit the market at any given time, again these are rare in any case and large quantities are never seen so values remain strong.