Green BIG ZEROS Scratch-off Coin. Mini liberty Coin. 1 bid Ending Saturday at 4:40PM PST 21h 19m. 1787 NOVELTY BENJAMIN FRANKLIN FUGIO CENT- AMERICA'S FIRST COIN.
Volume is defined as the number of digital coins that have been traded within the last 24 hours. Big Blocks Help Clear Throughput. Volume is defined as the number of digital coins that have been traded within the last 24 hours. Big Blocks Help Clear Throughput. The market cap of a cryptocurrency is calculated by multiplying the number of coins or tokens in existence by its current price. Volume is defined as the number of digital coins that have been traded within the last 24 hours.
The United States Mint has minted over 20 different kinds of coins, of many different sizes. Often, it is difficult for people to get a grasp of what much of the historical coinage looked like, at least in relation to modern circulating coins. This chart shows all of the coin types, and their sizes, grouped by coins of similar size and by general composition.[1]
Seven distinct types of coin composition have been used over the past 200 years: three base coin alloys, two silver alloys, gold, and in recent years, platinum and palladium. The base metal coins were generally alloys of copper (for 2 cent coins and lower), and copper/nickel (for 3 and 5 cent coins). Copper/nickel composition is also used for all modern 'silver' coins.[2]
| Steel Alloy | Copper | Copper Alloy | Silver Alloy | Silver | Gold | Platinum | Palladium | |||
|---|---|---|---|---|---|---|---|---|---|---|
| Three Cent 14 mm 0.8 g 0.750 fine 1851–1853 14 mm 0.75 g 0.900 fine 1854–1873 | ||||||||||
| Half Dime 15.5 mm 1.24 g 1794–1873 | Dollar 15 mm 1.67 gr 1849–1889 | $5 American Gold Eagle 16.5 mm 3.11 g 1986–present | $10 American Platinum Eagle 16.5 mm 3.11 g 1997–present | |||||||
| Three Cent 17.9 mm 1.94 g 1865-1889 | Dime (Clad) 17.91 mm 2.268 g 1965–present | Dime 17.9 mm 2.5 g 1796–1964 | $2.50 Gold Quarter Eagle 18 mm 4.2 g 1796–1929 | |||||||
| Small Cent 19.05 mm 2.5 g 1943 | Small Cent 19.05 mm 3.11 g 1864-1982 | Small Cent 19.05 mm 4.67 g 1856-1864 2.5 g 1982–present | Three Dollar 20.5 mm 5.01 g 1853–1876 | |||||||
| Nickel 21.21 mm 5 g 1866–present | Nickel 21.21 mm 5 g 1942–1945 | Twenty Cent 22 mm 5 g 1875–1878 | $5 Half Eagle 21.6 mm 8.36 g 1795–1929 | $10 American Gold Eagle 22 mm 7.78 g 1986–present | $25 American Platinum Eagle 22 mm 7.78 g 1997–present | |||||
| Half Cent 23.5 mm 6.74 g 1795–1857 | Two Cent 23 mm 6.22 g 1864-1873 | Quarter (Clad) 24.26 mm 5.67 g 1965–present | Quarter (40% Ag) 24.3 mm 5.75 g 1976(S) | Quarter 24.3 mm 6.25 g 1796–1964 | ||||||
| Dollar 26.5 mm 8.1 g 1979–Present[3] | $10 Eagle 27 mm 17.5 g 1795–1933 | $25 American Gold Eagle 27 mm 17.5 g 1986–present | $50 American Platinum Eagle 27 mm 15.6 g 1997–present | |||||||
| Large Cent 29 mm 10.89 g 1793–1857 | Half Dollar (Clad) 30.61 mm 11.34 g 1971–present | Half Dollar (40% Ag) 30.6 mm 11.5 g 1965–1970, 1976(S) | Half Dollar 30.6 mm 12.5 g 1796–1964 | |||||||
| $50 American Gold Eagle 32.7 mm 31.1 g 1986–present | $100 American Platinum Eagle 32.7 mm 31.1 g 1997–present | |||||||||
| $20 Double Eagle 34 mm 35 g 1849–1933 | $25 American Palladium Eagle 34.036 mm 31.120 g 2017–present | |||||||||
| Dollar (Clad) 38.1 mm 22.68 g 1971–1978 | Dollar (40% Ag) 38.1 mm 24.59 g 1971(S)-1976(S) | Dollar 38.1 mm 26.73 g 1794–1964 | ||||||||
| $1 American Silver Eagle 40.6 mm 31.1 g 1986–present | ||||||||||
| Steel Alloy | Copper | Copper Alloy | Silver Alloy | Silver | Gold | Platinum | Palladium | |||
|---|---|---|---|---|---|---|---|---|---|---|
Notes on the tables:
- Images are close to actual size on a 92-dpi monitor.
- Clad Half Dollars, Silver Half Dollars and Dollars, and Gold Half Eagles and Eagles are still regularly minted as commemorative coins. Dimes, quarters and half dollars are also struck in 90% silver for special annual collector's sets.
- The silver-colored Susan B. Anthony dollar was replaced with gold-colored Sacagawea Dollar in 2000 and Presidential Dollars 2007-2016; though the composition changed, the coin's size and weight remain the same.
- Some variances in coin size and weight occurred over time, especially as the value of silver varied. In particular, many silver coins changed in the 1870s. The figures cited in the tables are representative of the series, and are generally the latest, or most common, figures for a given coin type.
The largest coin ever minted by the US Mint was a gold 'Half Union' pattern in 1877, weighing 83.45 grams, and 51.1 mm in diameter. The largest coin actually issued by the mint was the Panama-Pacific Exposition $50 gold commemorative, at 83.572 grams and 44 mm. An octagonal version of the coin was slightly larger, measuring 45 mm at its widest point.
References[edit]
- ^'The United States Mint: Frequently Asked Questions'. Archived from the original on 28 March 2010. Retrieved 24 March 2010.
- ^'Coin Composition, Federal Reserve Bank of Atlanta'. Archived from the original on 8 June 2010. Retrieved 24 March 2010.
- ^'Native American $1 Coin'. Retrieved 25 March 2016.
How Bitcoin Mining Works
Where do bitcoins come from? With paper money, a government decides when to print and distribute money. Bitcoin doesn't have a central government.
With Bitcoin, miners use special software to solve math problems and are issued a certain number of bitcoins in exchange. This provides a smart way to issue the currency and also creates an incentive for more people to mine.
Bitcoin is Secure
Bitcoin miners help keep the Bitcoin network secure by approving transactions. Mining is an important and integral part of Bitcoin that ensures fairness while keeping the Bitcoin network stable, safe and secure.
Links
- We Use Coins - Learn all about crypto-currency.
- Bitcoin News - Where the Bitcoin community gets news.
- Bitcoin Knowledge Podcast - Interviews with top people in Bitcoin
Bitcoin Mining Hardware Comparison
Currently, based on (1) price per hash and (2) electrical efficiency the best Bitcoin miner options are:
AntMiner S7
- 4.73 Th/s
- 0.25 W/Gh
- 8.8 pounds
- N/A
- 0.1645
Big Coins Machine
AntMiner S9
- 13.5 Th/s
- 0.098 W/Gh
- 8.1 pounds
- N/A
- 0.3603
- Overview - Table of Contents
Bitcoin mining is the process of adding transaction records to Bitcoin's public ledger of past transactions or blockchain. This ledger of past transactions is called the block chain as it is a chain of blocks. The block chain serves to confirm transactions to the rest of the network as having taken place.
Bitcoin nodes use the block chain to distinguish legitimate Bitcoin transactions from attempts to re-spend coins that have already been spent elsewhere.
What is Bitcoin Mining?
Big Coins Wikipedia
What is the Blockchain?
Bitcoin mining is intentionally designed to be resource-intensive and difficult so that the number of blocks found each day by miners remains steady. Individual blocks must contain a proof of work to be considered valid. This proof of work is verified by other Bitcoin nodes each time they receive a block. Bitcoin uses the hashcash proof-of-work function.
The primary purpose of mining is to allow Bitcoin nodes to reach a secure, tamper-resistant consensus. Mining is also the mechanism used to introduce Bitcoins into the system: Miners are paid any transaction fees as well as a 'subsidy' of newly created coins.
This both serves the purpose of disseminating new coins in a decentralized manner as well as motivating people to provide security for the system.
Bitcoin mining is so called because it resembles the mining of other commodities: it requires exertion and it slowly makes new currency available at a rate that resembles the rate at which commodities like gold are mined from the ground.
What is Proof of Work?
A proof of work is a piece of data which was difficult (costly, time-consuming) to produce so as to satisfy certain requirements. It must be trivial to check whether data satisfies said requirements.
Producing a proof of work can be a random process with low probability, so that a lot of trial and error is required on average before a valid proof of work is generated. Bitcoin uses the Hashcash proof of work.
What is Bitcoin Mining Difficulty?
The Computationally-Difficult Problem
Bitcoin mining a block is difficult because the SHA-256 hash of a block's header must be lower than or equal to the target in order for the block to be accepted by the network.
This problem can be simplified for explanation purposes: The hash of a block must start with a certain number of zeros. The probability of calculating a hash that starts with many zeros is very low, therefore many attempts must be made. In order to generate a new hash each round, a nonce is incremented. See Proof of work for more information.
The Bitcoin Network Difficulty Metric
The Bitcoin mining network difficulty is the measure of how difficult it is to find a new block compared to the easiest it can ever be. It is recalculated every 2016 blocks to a value such that the previous 2016 blocks would have been generated in exactly two weeks had everyone been mining at this difficulty. This will yield, on average, one block every ten minutes.
As more miners join, the rate of block creation will go up. As the rate of block generation goes up, the difficulty rises to compensate which will push the rate of block creation back down. Any blocks released by malicious miners that do not meet the required difficulty target will simply be rejected by everyone on the network and thus will be worthless.
The Block Reward
When a block is discovered, the discoverer may award themselves a certain number of bitcoins, which is agreed-upon by everyone in the network. Currently this bounty is 25 bitcoins; this value will halve every 210,000 blocks. See Controlled Currency Supply.
Additionally, the miner is awarded the fees paid by users sending transactions. The fee is an incentive for the miner to include the transaction in their block. In the future, as the number of new bitcoins miners are allowed to create in each block dwindles, the fees will make up a much more important percentage of mining income.