Summary

Limited quantity, once these are sold there are no more.

Material: neodymium, exceptionally powerful, these large sizes must be treated with extreme caution, any fingers caught between two of these will be completely crushed. Treated with care, these are just amazing.

Choice of two sizes.

How does this compare with our other magnets?

Strengths

How many sheets of paper* will this magnet hold securely onto a fridge door?

Answers:
- smaller (10X30mm) 75
- larger round (20X30mm) 90

* A4 in size, 90gsm in weight (heavier than standard copy paper).

Uses for testing

Gold and silver are not magnetic. So when you are presented with dozens of items to test, save time by picking out all the items that are magnetic.

This does NOT mean that there are special magnets for testing gold and silver. If an item is NOT magnetic, it could be...anything (including gold and silver).

Silver is not magnetic, but silver is strongly diamagnetic. If you slide an appropriate magnet down a flat silver surface (e.g. a coin) it will move slowly instead of 'falling off'. Copper is slightly diamagnetic. See our .

Copper is not magnetic, neither is brass (a mixture of copper and zinc) or bronze (a mixture of copper and tin). A magnet is useful because many copper / bronze / brass items are really steel that has been plated and will (in most cases) be magnetic. So if an item is magnetic it cannot be solid copper / bronze / brass. Being magnetic does not prove it's steel, not all steel is magnetic.