More than 800 Million have been struck to date, all dated 1780 The thaler became the unofficial currency in some areas of Africa and Asia, and is still in use today as a "trade silver dollar" in many Arabian bazaars.
First, it is highly unlikely your coin was struck in 1780, the Maria Theresa thaler has been struck in large quantities from 1780 all the way to the present day. If you are really interested, there are ways to determine by the die if yours is an older strike or a newer one. But generally, these coins sell for silver scrap, or perhaps a bit more. You should easily be able to sell it for $20-25 depending on the price of silver.
Most Maria Theresa Thalers are modern restrikes and generally trade for close to silver melt, about $20-21 at present. Don't let the date fool you, nearly all the coins were minted well after 1780 and indeed continue to this present day, still with the date of 1780.
I assume you're referring to a Maria Teresa thaler, probably dated 1780.This is actually a bullion coin that's been struck in a number of countries, with the same date and design ever since then. It's sold for its silver value, not for spending. It sells for a bit more than the price of 1 oz of silver. That number changes a lot so you'll need to look in the business section of a newspaper or Google silver AND "spot price" to get an idea of its current value.
It depends greatly on the coin. Thalers (spelled a number of different ways including taler, tallar, dalar, etc.) were used for many years in Germanic/Austrian countries. The most common, and indeed the only one that has been minted continually, would be the Maria Theresa Thaler dated 1780. Such coins have been made from 1780-today with the 1780 day and so they don't have much collector value for modern specimens (although there are people who collect them by micro-variety). Such coins are ~83.3% pure silver and trade close to silver melt about $20-30 depending on the spot price of silver. However, there are a multitude of different other thalers, many with MUCH higher prices, although the exact price depends on the type/date of the coin and the condition.
If you mean a United States silver dollar none were produced until 1794.
< p> Yes
The first US silver dollars were dated 1794. Please check again and post a new question.
The CAROLUS IIII DEI GRATIA coin to which you possibly refer was a large silver Spanish-American Eight Reale (pieces of Eight) coin minted at various mints in Spain, Mexico, South and Central America. Due to a shortage of suitable metals during the Naploenic Wars, and a general shortage of circulating currency, the English acquired and countermarked the Spanish-American 8 Reale coins (and others) and used them as "Emergency Issue", referring to them as "Spanish Dollars". The Spanish-American 8 Reales coins were countermarked with a small image of George III and circulated as Four Shillings and Ninepence until 1811. Any of these coins in any reasonable condition, as long as they are identifiable and legible, might fetch well over £100 GBP.
Coins with this design have been issued by numerous countries since the original was struck. All bear the date 1780 regardless of when they actually were struck. Virtually all of the ones on the market now are not true coins, but instead are bullion pieces meant for people who want to buy a small amount of silver in a recognized form. As such, your piece is almost certainly worth the spot price of an ounce of silver, around $17 as of 06/2008.
There are a few things to realize about a 1780 Maria Theresa Thaler: Your coin was NOT minted in 1780, the Austrian mint has produced Maria Theresa Thalers fixed at Maria Theresa's death in 1780, most likely your coin was made in the 20th or 21st century. That doesn't mean your coin is worthless it just means that your coin isn't several hundred years old. Since they are restrikes, they don't have much of a premium over silver value, today they run around $25-30 depending on silver price and the condition of the coin.
There are a lot of misunderstandings about this coin ! It has nothing to do with mother Teresa - of course, it is : Maria Theresia, Empress of Austria. The problem with this coin is, that there are about 800.000.000 coins struck in the 20th century, but with the original date 1780 ! Value : only 20 dollars...