Sembia

Sembian coins have the arms of Sembia on one side, and the denomination (above) and the date (in DR) curving around a proof stamp [mint mark] on the other (yes, curving, regardless of the shape of the coin). Sembian coins often have a bluish tinge to them from being cleaned (of the grease they get on them from the stampings) by being held in a flame. The grease is deliberately “cooked into” the iron coins, to inhibit rust (it does a fair, not foolproof, job).

Cormyr

Modern Cormyrean coins bear the monarch’s face and name on side, and a date, denomination, and mint mark [almost always a full-on bearded, hatless wizard’s face, known as “Old Vangey,” which denotes the Royal Mint in Suzail, but in about ten percent of coins two parallel crescent moons, horns to the dexter, denoting a High Horn minting] on the other. There’s only been one minting since the death of Azoun IV, and these Regency coins bear the Purple Dragon royal arms with five parallel bars on its body, rather than the face of the infant monarch or of Alusair. Elder Cormyrean coins (eighty years old and older) don’t have dates, but instead “first minting,” “second minting,” and so on, these numbered mintings denoting times during the reign of that monarch that coins were issued (there were eight mintings in the reign of Azoun IV, but three mintings is as high a count as most of the early kings got). They are otherwise identical to more modern coins of the Forest Kingdom.

Cormyrean coins are of very pure metal and heavy weight, and age well, Sembian coins slightly less so -- but the coinages of Waterdeep, Luskan, Mirabar, Silverymoon, Amn, Tethyr, Cormyr, and Sembia are considered the best-made in Faerun, and are most highly valued in trade.

Tradebars

Tradebars are widely accepted, because they MUST conform closely to a given size and weight to be accepted at all. They are the best way to melt down and re-use “suspicious” coins, because an existing tradebar can be pressed into clay to easily make a mold for the new one.

A 25-gp tradebar is a “brick with rounded corners” (squared corners broke off too easily, and unscrupulous persons deliberately broke off corners whenever they could, so the custom of rounded corners became the norm) of just over an inch thick, three inches across, and six inches in length. Calishite tradebars (also used in Tharsult, Tashluta and the Tashalar, and other Southern trade) are seven inches long, but both ‘long sides’ bow smoothly inwards half an inch on each side, making the bar easier to grip.

A 50-gp tradebar is the same dimensions around their bottoms as 25-gp bars, but are three inches thick, and taper inwards as they rise (to look more like our real-world ‘ingot bars’), so their top surfaces are a half-inch smaller, all around. There are no (legal) bow-sided 50-gp tradebars.

A 75-gp tradebar is an inch thicker (taller) than a 50-gp bar, with no taper to its sides at all.

A 100-gp tradebar is two inches thick, three inches across, and nine inches long, with a central hole (for carrying or for passing a cord through, to tie into bundles). The hole shouldn’t be much more than an inch across.
Proof and ownership marks are commonly stamped into the bottom surface of a tradebar, and don’t affect value.

Very early tradebars vary widely in dimensions and value, but are either weighed and valued at that time when traded today, or melted down when they must be transferred from one owner to another.

Old and Ancient mints

Acceptance of older coins depends on condition and metal: gold coins are accepted everywhere at face value unless they’re broken, unusually small, or obviously impure. Silver coins that have tarnished to black are seldom accepted, but if PCs clean them WITHOUT highly abrasive means that take much of the markings off, they’ll probably be accepted, too (again, unless broken, impure, or small). For everything else, yes, go to a moneychanger (most cities on any coast have several).