A keeper, for sure. Weight is correct, this is struck on a 1-cent planchet. Still nice and red, I estimate it to be MS-62 or MS-63, at best.
Still haven't learned, have you? Try looking at post number 19 in this thread http://www.cointalk.com/t216262-2/
Just a guess, but it was a good example of the polite way to ask such a question. OP, Very nice. Congrats!
Because you asked the question in a polite manner. I used it as a teaching tool. I hope you don't mind, but if you do, I'll remove it.
I paid a slight premium for this sealed mint bag, since there are two denticle varieties for 1978 25-cent coins. I paid 3x face value for the bag. So, this error cost me $0.75. I collect Canadian small cent errors, so this coin is worth nothing to me - because it will not see an auction block for a very long time. Coins are only worth what people are willing to pay you for them, at the time of sale. As for market value, Google is your friend. Several examples of this error have come up for auction in recent years, through icollector and Heritage, so look them up. As I tell my graduate students, "I am not doing their research, for them." Recent prices realized are of no concern to me (see above).
Whatever a knowledgeable collector is willing to pay for it. Note: It may NOT be worth what an unknowledgeable collector is willing to pay for it.