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- Increasing international collaboration
- Industry growth centres
- Industry Innovation and Science Australia
- National Measurement Institute
- Optical astronomy in Australia
- Participating in the digital economy
- Promoting innovation precincts
- Science in our department
- Science, technology, engineering and mathematics (STEM)
Energy
Resources
Northern Australia
Trade
Business support
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Government to government services
- Regulations and standards
Emissions reduction
Energy
Resources
- Applying to export rough diamonds
- Applying to export uranium and controlled ores
- Offshore mineral exploration and mining
- Offshore oil and gas exploration and development
- Offshore petroleum exploration acreage release process
- Regulating offshore oil and gas in Australian Commonwealth waters
- Regulating the Ranger Uranium Mine
- Taxes and royalties on minerals and petroleum
Measurement
Trade
Space industry
Building industry
Business support
- Funding and incentives
Emissions reduction
Industry innovation and science
- Australian Square Kilometre Array Fellowships Programme
- Business Research and Innovation Initiative
- Business-research collaboration
- Collaborating with Asia-Pacific on science, research and innovation
- Collaborating with China on science and research
- Collaborating with India on science and research
- Cooperative research centres
- Enabling international space investment
- Industry 4.0
- Inspiring Australia: Science engagement in Australia
- International research collaboration
- Moon to Mars: opportunities for Australian businesses
- Prime Minister's Prizes for Science
- Research and Development Tax Incentive
- Supporting advanced manufacturing
- Supporting business and innovation
- Supporting space infrastructure growth
- Transitioning Australia’s automotive manufacturing industry
- Venture capital
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COVID-19
Jobs
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- Organisation chart
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- Overseas engagement
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- Anti-Dumping Review Panel
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- National Measurement Institute
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Precious metals and stones

Trade measurement laws regulate the buying, selling and valuating of precious stones or metals when using a measuring instrument, such as a scale.
These laws do not cover other factors you consider when determining price, including:
- metal purity
- colour
- link type
- workmanship
- rarity
- design popularity
Weighing precious stones
Any scale you use to weigh diamonds or other precious stones must not have a verification scale interval of more than:
- 10 mg
- 0.01 metric carats (CM) where the capacity of the instrument is less than 5000 CM
- 0.05 CM where the capacity of the instrument is at least 5000 CM
The verification scale interval is the graduation size that a scale will calculate weight by, for example a gram, milligram or metric carat increment.
Weighing precious metals
You can’t use a scale to weigh gold, silver or other precious metals when it has:
- a verification scale interval that is greater than the interval specified for the scale’s capacity
- a capacity specified in the first column of the following table, unless it has a verification scale interval equal to or less than that specified in the second column
Capacity of instrument | Verification scale interval |
---|---|
Less than 1 kg | 10 mg |
1 kg or more but less than 10 kg | 100 mg |
10 kg or more | 1 g |
If you use a scale below the minimum capacity marked on the data plate it can be inaccurate.
A verification scale interval is denoted as the ‘e’ value marked on the data plate of a scale. Before purchasing a scale, you should check the ‘e’ value to ensure that it meets these requirements.
Using scales
If you use a scale to weigh precious metals or stones, you must ensure that:
- the National Measurement Institute (NMI) has approved your type of scale
- a servicing licensee has verified your scales
- you and your staff use the scales in the correct manner (e.g. level and indicating zero before use)
- you position the scales so that the customer can easily see the weighing process (if not, you must provide a written statement of the weight)
- you keep the scales clean and in good working order
- a servicing licensee verifies the scales after each repair or adjustment
You are responsible for making sure the scale is correct at all times.
We recommend that you check your scales daily to ensure their accuracy. You can purchase a set of test weights from a certifying authority to check that your scales are level, resets to zero and accurate.
We also recommend that you have your scales checked regularly by a technician licensed by NMI (servicing licensee). For a list of servicing licensees, email tmlicensees [at] measurement.gov.au.
Regulating the sale and valuation of precious metals and stones
The National Measurement Act 1960 and the National Trade Measurement Regulations 2009 regulate how precious metals and stones are sold by measurement.
NMI employs trade measurement inspectors throughout Australia. They inspect precious metals and stones being sold or valuated to ensure that sellers are following the correct process.
If an inspector finds that you are short-measuring your customers, you could be fined up to $222,000 per offence.
Read more
Find out what to do if you get a visit from a trade measurement inspector
Contact us
To find out more about trade measurement laws or report a suspected breach contact the trade measurement helpline:
- Email infotm [at] measurement.gov.au (subject: Trade%20Measurement%20Law, body: Name%3A%0A%0AEmail%3A%0A%0APhone%3A%0A%0AAddress%3A%0A%0ADetails%3A)
- Phone 1300 686 664

- National Measurement Institute
Last updated: 8 December 2020
Content ID: 52557