Reference

Coin and storage glossary

Plain-English definitions of the terms you will meet when collecting and storing coins, from capsule types to coin finishes and measurements.

Storage and capsules

Direct fit capsule: A capsule moulded to one coin diameter, so the coin drops straight in with no ring. Slim and edge-to-edge clear. See our direct fit vs black ring guide.
Black ring capsule: A capsule with a foam or acrylic ring that frames the coin, letting one capsule size suit a range of smaller coins and giving a presentation border.
Inside diameter: The internal measurement of a capsule, the figure that must match your coin. We list it on every product page so you can match it precisely.
PVC-free: Made without polyvinyl chloride. Soft PVC can release chemicals that damage coins over time, so archival storage uses inert, PVC-free acrylic.
Storage tube: A rigid tube that holds a stack of capsules of one size, keeping a set together and adding a barrier against light and dust. Browse storage tubes.

Bullion coin: A coin bought primarily for its precious-metal content rather than rarity, such as a Krugerrand or Britannia.
Proof: A coin struck with specially prepared dies and blanks to give a mirror-like field and frosted design. Proofs are collector pieces and especially worth protecting.
Uncirculated / bullion strike: A standard production finish, as opposed to proof. Still worth keeping in a capsule to preserve the surface.
Toning: The natural colour a coin develops as its surface reacts with the air over years. Often prized rather than seen as a fault, which is one reason never to clean a coin.
Fineness / purity: How pure the metal is, written as a decimal or in parts per thousand. .999 means 99.9% pure; .9999 (four nines) is 99.99%.

Obverse and reverse: The two faces of a coin. The obverse is the "heads" side (often a portrait); the reverse is the "tails" side (often the main design).
Field: The flat, blank area of a coin around the design. Fields show fingerprints and hairline scratches most readily.
Reeded edge: The fine grooves milled into the edge of many coins. Originally a check against clipping precious metal from the rim.
Relief: How far the design is raised above the field. High-relief coins, such as the 2 oz Queen's Beast, are thicker and need a deeper capsule.
Diameter: The width of a coin across its widest point, in millimetres, the measurement that decides which capsule fits. Use our capsule finder or size guide.

Troy ounce: The standard unit for precious metals, about 31.1 grams, slightly heavier than the everyday (avoirdupois) ounce.
Fractional: A coin issued in a part-ounce size, such as 1/2, 1/4 or 1/10 oz. Fractionals are smaller in diameter and take smaller capsules.
Face value: The legal-tender value stamped on a coin. For bullion this is usually far below the metal value and is largely symbolic.
Spot price: The current market price of a precious metal, against which bullion coins are bought and sold (plus a premium).

Ready to protect your coins? Try the capsule finder or browse the full capsule range.