Two stamps can look very similar from the front but differ considerably when you turn them over. For mint and unused stamps, the gum and any evidence of mounting are important parts of the description.
Understanding those differences helps you choose what suits your collection, whether you want pristine examples or attractive stamps at a more accessible price.
The main photograph shows a 1929 Postal Union Congress 1d K29 block of six. The blue arrows highlight printing varieties, not mounting marks.
Unmounted mint
An unmounted mint stamp has not been attached to an album with a stamp hinge and retains its original gum without hinge marks.
You may also encounter the terms “never hinged” or “mint never hinged”. In our descriptions, we use “unmounted mint” in full.
Unmounted mint does not automatically mean perfect in every respect. A stamp may still have toned gum, a gum crease, short perforations or another fault. Those details matter alongside its mounting status and should be described separately.
Mounted mint
A mounted mint stamp retains original gum but has been mounted using a stamp hinge, usually to hold it in an album.
A hinge is a small piece of gummed paper folded between the stamp and the album page. It can leave a mark, disturb the gum or remain partly attached when the stamp is removed.
“Lightly mounted mint” describes an example with relatively slight evidence of hinging. It does not mean unmounted mint.
For many collectors, an attractive mounted mint stamp offers a practical way to collect an issue without paying the premium that an equivalent unmounted example may command.
Reverse of the same block. The mounted stamp is the top-left stamp when viewed from the front, corresponding to the top-right stamp in this reverse photograph. The remaining five stamps are unmounted mint.
View this 1929 PUC block of six
Unused and without gum
“Unused” tells you that a stamp has not been postally used, but the word alone does not establish the condition or originality of its gum.
An unused stamp may have original gum, partial gum or no gum. Where gum is absent, look for a clear description such as “unused, no gum” rather than assuming it is mint with original gum.
There are also stamps originally issued without gum, so the expectations depend on the particular issue.
Why the reverse matters
The front shows the design, colour, centring and much of the visible condition. The reverse helps reveal mounting traces, gum condition and faults such as thinning.
A stamp that looks excellent face up may have a hinge remnant or disturbed gum. Equally, a small hinge mark may be an acceptable compromise for a collector who values the appearance of the front.
Photographs of both sides are particularly useful when comparing individual examples.
What about regummed stamps?
Regumming means gum has been applied after the stamp was originally issued. A regummed stamp is not equivalent to an unmounted mint example with original gum, even if its reverse looks clean.
Assessing gum originality can require specialist experience. For an expensive stamp, a suitable expert certificate may be worth considering.
Which condition should you collect?
There is no single right answer. Your budget, the availability of the issue and your collecting aims all matter.
Some collectors prioritise unmounted mint throughout. Others happily choose lightly mounted mint or unused examples to build a broader collection.
The important thing is to know what you are buying and compare like with like. When consulting a catalogue, check which condition its valuation refers to. A mounted mint valuation should not automatically be treated as an unmounted mint valuation, or vice versa.
At GBstamps.net, our descriptions distinguish mounting status from other condition details, including gum toning and hinge remains where applicable. If you would like clarification about a particular stamp, please ask before purchasing.
Browse our current stamp listings to compare the condition descriptions and find examples that suit your collection.