No they are not, in general just because a coin has a mintmark does not make it more valuable.
Before 1965 in most cases. While error coins can be found on any coin from the earliest coins to the present, all other coins that are valuable were minted before 1965. Any dime, quarter, or half-dollar minted before 1965 was minted in 90% silver making it worth more than face based on that only, no matter how common the year was.
Valuable
There's no specific answer. A coin can be valuable because it's scarce or made of precious metals. Some old coins were minted in such large quantities that they're still common among collectors while other more modern coins were only made in small numbers and are worth a lot more. Even within the same date and denomination, values can differ radically. Among US coins, for example, a 1909 Lincoln cent from Philadelphia that doesn't have the designer's initials VDB can be bought for a few dollars because millions were struck. However only about 484,000 such coins that did have the designer's initials were made at San Francisco; these can be worth hundreds or thousands of dollars.
It's called a mint mark and identifies the mint that struck the coin. See the Related Question for more information.
Yes - consecutive serial numbers make them more valuable, when sold.
No. They are just more valuable coins. These are the coins from least valuable to most valuable: yellow, red, blue.
They are not valuable, they are still in circulation and are worth 50 Pence. Newer coins only have some value if they are in mint uncirculated condition or, if they are Proof coins. Due to the extra work put into them and the metals they are made from, Proof coins are more expensive to buy in the first place.
Just because a coin was struck at the Denver Mint does not make it more valuable. But some D mint coins are more valuable, it depends on the date, denomination and condition of the coin.
For a numismatic collection the non-circulated coins are more valuable. The price difference between circulated an non-circulated coins is very important in catalogs.
Some more than others. For more valuable coins, they have to be pre-WWII. Postwar coins are only worth 3-10 cents each.
It depends on the coins date and mintmark. Modern DCAM Proof coins are very common and so are Mint State coins.
Some more than others. For more valuable coins, they have to be pre-WWII. Postwar coins are only worth 3-10 cents each.
Silver is valuable. As of 04/2009 the raw metal has been selling in the range $12-13 an ounce. If it's in coins or jewelry it may be more valuable as a collector's item.
In general no. Just because a dime has a mintmark does not make it more valuable.
Not for general circulation as the metal is far more valuable the the face value of coins being minted, however silver may be added to very special commemorative coins.
It depends on the coin. Some are only worth their bullion value, if it's a common date in circulated condition (such as a 1964 Washington quarter). If it's a rare date, or it's in mint condition, then it's more valuable to collectors.
I would try the Grand Exchange. Since normal logs are not particularly valuable (51 coins at the time of this writing), you might also just burn them - and thus train your firemaking skill - until you are able to get more valuable logs.I would try the Grand Exchange. Since normal logs are not particularly valuable (51 coins at the time of this writing), you might also just burn them - and thus train your firemaking skill - until you are able to get more valuable logs.I would try the Grand Exchange. Since normal logs are not particularly valuable (51 coins at the time of this writing), you might also just burn them - and thus train your firemaking skill - until you are able to get more valuable logs.I would try the Grand Exchange. Since normal logs are not particularly valuable (51 coins at the time of this writing), you might also just burn them - and thus train your firemaking skill - until you are able to get more valuable logs.