A guitar pick is a plectrum used for guitars. A pick is generally made of one uniform material; examples include plastic, rubber, felt, tortoiseshell, wood, metal, glass, and stone. They are often shaped in an acute isosceles triangle with the two equal corners rounded and the third corner rounded to a lesser extent.
Pick shapes started with guitarists shaping bone, shell, wood, cuttlebone, metal, amber, stone or ivory to get the desired shape. Most of today's guitar pick shapes were created by the company that made the first plastic pick in 1922, D'Andrea Picks. The plastic pick was an idea that Luigi, and his young son Tony, Sr., had after purchasing sheets of tortoise shell-like celluloid from a street vendor. It appeared similar to the real tortoise shell picks used in their Greenwich Village neighborhood.
An early popular shape, the 351, is the rounding off of the top of heart. The rounded triangle is the 346 and the small jazz pick, the 358. All these represent the numbers the Luigi & Tony D'Andrea assigned to each of their new creations at the request of the guitarists they serviced. Soon after, they requested their names be imprinted on them. D'Andrea Picks was the first company to create custom pick imprinting in 1938, allowing customers to order imprinting up to 12 block letters. One of the first to make the player imprint popular was guitarist Nick Lucas in the early 1930s.
In rock and heavy metal, while playing electric guitar with hi-gain amplification or distortion, thinner picks produce muddier, heavier, less controllable sound and thicker picks produce more delicate, more controlled and well-shaped tone. Thinner picks also tend to rip or tear more often if used too forcefully, whereas a thicker one is less likely to wear down. Thicker picks are generally used in more discrete genres, such as heavy metal or power metal. However, there are many exceptions to these stereotypes, especially as there is an element of guitarist preference involved in selecting pick thickness.
Many death metal musicians only use picks thicker than 1.5mm, because it allows more control over heavy gauge strings. Thinner picks tend to give less attack and do not give as much control when doing fast tremolo picking. Also, they tend to wear much faster when used with heavier gauge strings.
Jazz guitar players tend to use quite heavy picks, as they also tend to favor heavy gauge flat-wound strings. Bass players tend to prefer thick picks because their strings are far thicker and farther apart than those of guitarists.
Some picks have small protrusions to make them easier to keep hold if the fingers start to sweat (very common on stage due to the hot lights). Some picks (as illustrated) will have a high-friction coating to help the player hold on to them. The small perforations in the stainless steel pick serve the same function. Many players will often have spare picks attached to a microphone stand or slotted in the guitar's pickguard.
The equilateral pick can be easier for beginners to hold and use since each corner is a playing edge.
The shark's fin pick can be used in two ways - normally employing the blunt end or the small perturbations can be raked across the strings producing a much fuller chord or used to employ a "pick scrape" down the strings producing a very harsh, scratching noise.
The sharp edged pick is used to create an easier motion of picking across the strings.
Bass players who use a pick normally use much heavier picks than guitar players. Some bass players find that coins make excellent picks, though some prefer slightly thinner picks to increase speed and endurance.
Some guitar pick shapes are patented. Usually those patents claim ornamental design.
Some picks are made of semi-precious gemstones including jasper, tiger eye, jade, quartz, and others.
Some picks are constructed of compound layers of plastic, connected to form a flexible central section, allowing the guitarist to adjust the pick tip's flexibility by applying various pressure to this central section: a hard grip yields hard pick (thicker one) to play lead, a soft grip yields soft pick (thinner one) to play rhythm.
Picks are usually gripped with two fingers—thumb and index—and are played with pointed end facing the strings. However, it's a matter of personal preference and many notable musicians use different grips. For example, Eddie Van Halen holds the pick between his thumb and middle finger (leaving his first finger free for his tapping technique); James Hetfield, Jeff Hanneman and Steve Morse hold a pick using 3 fingers—thumb, middle and index; Pat Metheny and The Edge also hold their picks with three fingers but play using the rounded side of the plectrum. George Lynch also uses the rounded side of the pick. Stevie Ray Vaughan also played with the rounded edge of the pick, citing the fact that the edge allowed more string attack than the tip. His manic, aggressive picking style would wear through pickguards in short order, and wore a groove in his beloved Fender Stratocaster, Number One, over his years of playing. Jimmy Rogers and Freddie King had a special kind of technique utilizing two picks at once. Noted 80's session guitarist David Persons is known for using old credit cards, cut to the correct size, angle, and thickness and using them without a tip.
The motion of the pick against the string is also a personal choice. George Benson and Dave Mustaine, for example, hold the pick very stiffly between the thumb and index finger, locking the thumb joint and striking with the surface of the pick nearly parallel to the string, for a very positive, articulate, consistent tone. Other guitarists have developed a technique known as circle picking, where the thumb joint is bent on the downstroke, and straightened on the upstroke, causing the tip of the pick to move in a circular pattern. Circle picking can allow speed and fluidity. The angle of the pick against the string is also very personal and has a broad range of effects on tone and articulation. Many rock guitarists will use a flourish (called a pick slide or pick scrape) that involves scraping the pick along the length of a round wound string (a round wound string is a string with a coil of round wire wrapped around the outside, used for the heaviest three or four strings on a guitar).
The two chief approaches to fast picking are alternate picking and economy picking. Alternate picking is when the player strictly alternates each stroke between downstrokes and upstrokes, regardless of changing strings. In economy picking, the player will use the most economical stroke on each note. For example, if the first note is on the fifth string, and the next note is on the fourth string, the pick will use a downstroke on the fifth string, and continue in the same direction to execute a downstroke on the fourth string. The economy picking technique sounds as though it would require more conscious thought to execute it but many guitarists learn it intuitively and find it an effort to use alternate picking. Conversely, some guitarists maintain that the down-up "twitch" motion of alternate picking lends itself to momentum, and hence trumps economy picking at high speeds.