Sacagawea Dollar
Shoshone guide Sacagawea carrying her infant son Jean Baptiste on her back, on a golden-colored coin. A soaring eagle surrounded by seventeen stars, one for each state at the time of the Lewis and Clark expedition.
Composition
Key dates to look for
2002-P Sacagawea
$4+ uncirculatedFirst year not released to circulation — Mint sets, bags, and rolls only
2004-P Sacagawea
$5+ uncirculatedLow-mintage collector-only year, never released for circulation
Valuable varieties & errors
2000-P 'Cheerios' Dollar (Enhanced Tail Feathers)
extremeMost of the dollars packed into Cheerios boxes were struck from an early prototype reverse die with extra-detailed eagle tail feathers. Only a few dozen have been confirmed, making this the top prize of the whole series.
2000-P 'Wounded Eagle'
rareA raised die gouge cuts straight across the eagle's belly on this variety, looking like a spear through the bird — hence the nickname. It comes from damage to one reverse die and is recognized by the grading services.
2000-P Goodacre Presentation Finish
rareDesigner Glenna Goodacre asked to be paid her $5,000 design fee in the new dollars, and the Mint struck her 5,000 coins with a special burnished finish. Most were later certified, and they trade as a distinct collectible.
Error types found on this series

Wrong Planchet
A coin struck on a blank intended for a different denomination or country — like a quarter design on a nickel blank.
Missing Clad Layer
A dime, quarter, or half is missing its outer silver-colored layer on one side, exposing the copper core.
Improperly Annealed Planchet
A heat-treatment mistake turned the blank's surface an unusual color — most famously the coppery-red 'sintered' state quarters and dollars.

Die Crack
A crack in the die fills with metal during the strike, leaving a thin raised line on the coin.
Real photos where available (credits); others are illustrations.