Chelsea Filter

Quicktest

£29.5

Summary The original Chelsea Filter, as developed at the Chelsea College of Science and Technology in 1934. Do not confuse this with the many copies. Detail Many stones appear to change colour when viewed through the filter. Originally designed for detecting synthetic emeralds, nowadays the Chelsea filter is an invaluable aid to identifying many other gemstones. It can give an indication that you have an emeralds and aquamarines, though not a guarantee, since there is considerable variation in their chemical compositions (e.g. the amount of chromium that gives the green colour and the amount o

Quicktest's own words, read from their page.

Buy from QUICKTEST LIMITEDQUICKTEST LIMITED is a UK retailer, not the maker. Price seen 2026-09-26. Not an affiliate link, we earn nothing from it.

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The part other shops don't tell you. Three separate questions, kept separate on purpose, each with its source.

UK company
Registered at Companies House as QUICKTEST LIMITED, number 06024230. Checked 2026-08-29.
Means the business is a British legal entity, not a British-sounding name owned elsewhere. It says nothing about where anything is made.
UK operations
Not yet checked.
Means people employed here, or premises they actually work from. We keep this separate from the company badge because a registered office can be an accountant's spare room, and a company can be registered in Britain while everything it does happens somewhere else. Where we have not looked, we say so rather than assuming.
British-owned
Not established. Many companies file a statement rather than naming a controlling shareholder.
Read from the register of people with significant control, following the chain of holding companies. It does not gate anything: a firm can be made here and owned elsewhere, and that is worth telling you rather than hiding.
Where it is made
The maker doesn't say, so neither do we.
This is about the individual product, not the company. A British firm can sell things made abroad, which is normal and not a criticism. We would rather tell you which is which than average them into a score.

Chelsea Filter

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