Checking Your Uranium Glass Collection with a Geiger Counter

Will a Geiger counter pick up uranium glass?

Yes, provided the counter is close to the glass. The US Environmental Protection Agency (EPA) page Radioactivity in Antiques explains that vaseline or canary glass contains a little uranium, which gives it its yellow-green colour, and that such objects can make a Geiger counter react when it is held near them. Radiation falls off quickly with distance, so a counter on the other side of the room will show little more than the room itself. Hold it against or very near the glass, let the reading settle, and compare it with a background measured first, away from the collection.

Identifying a piece is a separate job: colour, age, marks and the glow under ultraviolet light are covered in depth in our guide to checking uranium glass and radium dials. This page is about the counter, what it adds to a UV check and where its limits lie. Whether it is a bowl that has sat in a family cabinet for years or a piece you have inherited, the counter is the second opinion that turns a hunch from the UV lamp into a number you can note down and compare.

How to check a piece: UV lamp first, then the counter

Start with a small UV lamp in a dim room: the EPA notes that uranium glass glows green under ultraviolet light, the quickest way to sort a box of glass. Then take a background reading with the counter, well away from the collection, and let the average dose rate settle. One independent test found that this type of glass tube gives about 20 CPM at background, and the figure moves from minute to minute, so averages matter more than any single number. Only then bring the counter to the piece.

Keep the same distance and the same side of the counter facing the glass for every object, so that the results can be compared. Read CPM rather than µSv/h: an independent test notes that the tube has no beta shield, so near beta sources the dose rate figure runs high, whereas CPM is the raw count from the tube. After a more active piece, let the counter fall back to background before moving on to the next one.

What the reading tells you, and what it does not

A reading clearly above background tells you one thing: the object gives off radiation the tube can see, at that distance. It does not tell you how much uranium the glass contains, it cannot say whether a piece is fine to use or display, and a dose rate taken against a bowl is not the dose anyone in the room receives. Readings are indicative, from a consumer detector for general information only. For context, the UK Health Security Agency (UKHSA) puts average exposure in the UK at about 2.6 mSv a year, and the EPA notes that background varies from place to place and rises with altitude.

Two habits keep the numbers honest. Compare CPM only with readings from the same counter: counts depend on the tube, so another collector's figure from a different device tells you little. And if you ever see an unusually high or persistent reading, move away from the object, do not handle it, and contact the UK Health Security Agency or your local authority. In an emergency, call 999.

Uranium-glazed pottery, radium dials and handling old pieces

The EPA also lists some American dinnerware made before 1973 with a uranium glaze, and luminous watch and clock dials that glow without a battery, which may contain radium. The agency adds that these objects, intact and in good condition, generally do not pose a problem, but the counter cannot confirm that for a given piece; it only shows a reading above background. A dial deserves the most care: measure it as it is, and never open it or take it apart.

The EPA handling advice applies whatever your counter shows. A low reading does not turn an old bowl into tableware, and a high one is a reason to leave the object alone and follow the warning above. The counter is for checking what you already own or are looking at, not a reason to go round car boot sales and antique fairs hunting for radioactive objects, or to seek out test sources.

• Keep objects intact.
• Never take apart a radium dial.
• Do not serve food or drink in old uranium-glazed pottery or uranium glass, as chips can end up in what you eat.
• Wash your hands after handling.
• If a piece breaks, ask your local authority how to dispose of it.

Why a long glass tube helps with glassware

With glassware you are looking for a modest rise over background, so the number of counts matters. This counter uses a glass Geiger-Muller tube of the J321 type, as listed by the supplier. According to the maintainer of an open-source firmware for these counters, short tubes of the J614 type are less sensitive at background than a J321, so the longer tube collects more counts, and more counts make a small difference easier to see in an average. An independent test found that it picks up hard beta, gamma and X-rays.

It shows real-time and average dose rate in µSv/h, count rate in CPM or CPS, cumulative dose in µSv, and a dose-rate trend graph that makes the rise near a piece easy to spot. Two alarms (dose rate and dose) have adjustable thresholds. The manufacturer gives a range of 0.01 µSv/h to 50 mSv/h and an energy response of 48 keV to 1.5 MeV. The built-in 1,800 mAh battery charges over USB-C: 30 days or more in long-life mode according to the manufacturer, about 5 days in normal use in an independent test.

What this counter will not do

The glass-walled tube sees beta, gamma and X-rays only. The least penetrating kind of radiation cannot get through the glass, so a flat reading is not proof that an object emits nothing. The counter cannot test food or water, is no substitute for a radon measurement pack, and does not react to Wi-Fi, 5G or other electromagnetic fields. It is not a reference measuring instrument and not approved by any agency. There is no Bluetooth and no app; the manufacturer describes a PC data download over USB-C with its own software, which we do not supply.

Geiger Counter Shop sells one product: this yellow pocket counter with its glass GM tube, 2.4-inch colour screen, µSv/h and CPM readings, trend graph, alarms and USB-C battery. UK orders ship free from stock in a UK warehouse, with no customs step: prepared in 1 to 2 working days, then delivered in 2 to 5 working days (indicative, not a guaranteed date), with a tracking number by email. Prices are shown in pounds sterling, VAT included.