Buying a jewellery scale in India starts with the law: Legal Metrology rules allow only Class I or Class II weighing instruments for weighing gold, silver, pearls and precious stones in trade. For a gold counter that means a scale that reads 0.01 g, and diamond or gemstone work needs one that reads 0.001 g. Omace sells Ace jewellery and pocket scales from ₹799 to ₹27,999 (October 2026), and the right one depends on what you weigh, how heavy it is and whether a price is set by that weight.
Legal Metrology rules for a gold-selling scale
A scale that sets the price of jewellery is a legal measuring instrument in India. The Delhi Legal Metrology (Enforcement) Rules, 2011 allow only a Class A or Class B beam scale, or a non-automatic weighing instrument of high accuracy (Class II) or special accuracy (Class I), for transactions in gold, silver, pearls, ornaments and precious stones. Each state makes its own enforcement rules under the Legal Metrology Act, 2009, so check your state's version as well.
The scale must also be verified and stamped, and the stamp expires. The Delhi Weights and Measures Department lists a validity of one year for an electronic scale and two years for bullion weights. The same department states a fine of ₹5,000 for using a weight or measure that has not been verified.
Hallmarking adds a second reason to weigh precisely. The Bureau of Indian Standards hallmarking brief requires every BIS-registered jeweller to keep a suitable weighing balance at the sales outlet. The sale invoice must show the net precious-metal weight of each article, and mandatory gold hallmarking covered 392 districts after the amendment of 3 August 2026.
Which readability: 0.1 g, 0.01 g or 0.001 g?
Readability is the smallest step the display shows. Choose it from the smallest piece you weigh and the material's value.
- 0.01 g (10 mg) for gold and silver ornaments. Rings, chains, bangles and old gold brought in for exchange all sit in this range. The Ace JS-6002 gold weighing scale weighs up to 600 g in 0.01 g steps and shows the weight on green LED displays at the front and the back.
- 0.001 g (1 mg) for diamonds, gemstones and tiny findings. One metric carat is exactly 0.2 g, according to the NIST table of SI conversion factors. A 0.001 g scale therefore reads in 0.005 ct steps, while a 0.01 g scale reads only in 0.05 ct steps. The Ace GM-50 carat scale weighs up to 50 g in 0.001 g steps and comes with a windshield, tweezer, dish and calibration weights.
- 0.1 g (100 mg) for heavy silver. Silver plates, glasses, idols and bars run into kilos. The Ace JS-10KG silver weighing machine weighs up to 10 kg in 0.1 g steps on a 170 x 170 mm steel pan.
A kitchen scale that reads in 1 g steps is too coarse for any of this work. On a 4 g pair of earrings, one 1 g step is a 25% change in the weight.
Readability is not accuracy: d, e and Class II
The step on the display, called d, is not the step the law checks. OIML R 76, the international recommendation for non-automatic weighing instruments, defines a separate verification scale interval, e, which can be up to ten times d. A scale that displays 0.01 g can carry e = 0.1 g on its data plate.
Permitted errors are counted in units of e. At initial verification, R 76 allows a Class II scale an error of half an e for loads up to 5,000 e and one e up to 20,000 e. With e = 0.1 g, a 100 g chain may read 0.05 g high or low and the scale still passes. With e = 0.01 g, the limit on the same chain is 0.01 g.
| Accuracy class | Verification interval e | Intervals (Max ÷ e) | Allowed for gold and gems in trade? |
|---|---|---|---|
| Class I (special) | 0.001 g or more | 50,000 or more | Yes |
| Class II (high) | 0.001 g to 0.05 g | 100 to 100,000 | Yes |
| Class II (high) | 0.1 g or more | 5,000 to 100,000 | Yes |
| Class III (medium) | 0.1 g to 2 g | 100 to 10,000 | No |
| Class III (medium) | 5 g or more | 500 to 10,000 | No |
R 76 also sets a minimum capacity, below which use of the scale is likely to give considerable relative errors. For Class II it is 20 or 50 scale intervals, which works out to 0.2–0.5 g on a scale that reads 0.01 g. Nose pins and small studs below that weight belong on a 0.001 g balance.
Before buying, ask the seller for the class, Max, Min, d and e marked on the scale, and for its model approval and verification papers.
Jewellery scale types compared
Omace groups its Ace jewellery weighing scales by readability and capacity. The table lists each type with its Omace price range.
| Type | Reads in | Capacity | Best for | Omace price (October 2026) |
|---|---|---|---|---|
| Pocket scale | 0.01 g | 200–500 g | Personal checks, travel | ₹799–₹2,499 |
| Pocket milligram scale | 0.001 g | 30–50 g | Loose stones in carats | ₹1,999–₹4,499 |
| Counter jewellery scale | 0.01 g | 600 g | Gold billing, old gold exchange | ₹2,999–₹9,999 |
| Precision weighing scale | 0.01 g | 1–2 kg | Heavy sets, workshops | ₹12,999–₹21,299 |
| Milligram balance with windshield | 0.001 g | 200–500 g | Diamonds, assay samples | ₹22,499–₹27,999 |
| Silver weighing machine | 0.1 g | 10 kg | Silver articles, bars | ₹12,999 |
A pocket scale suits quick personal checks and travel; the full range sits under pocket scales. A counter scale has a wider pan, 130 mm on the 600 g Ace models, and stays set up in one place; the guide to pocket scale vs bench scale compares the two in detail. Whatever you buy, the scale that sets a customer's price must be the one with the valid stamp.
For diamonds and gemstone grading, the Ace JS-3003 precision weighing balance weighs up to 300 g in 0.001 g steps inside a glass windshield and comes with a 200 g calibration weight.
Units: grams, carats, tola and hallmark purity
Ace counter scales switch between grams, carats and tola with the UNIT key. Use grams for billing and carats for gemstones; many customers still ask for tola.
- Carat (ct): exactly 0.2 g, so a 0.5 ct diamond weighs 0.1 g.
- Grain (gr): exactly 64.79891 mg in the NIST table.
- Tola: 11.6638 g, which is 180 grains.
- Troy ounce (oz t): 31.10348 g.
- Karat (K): a purity grade, not a weight. A 22K article holds at least 916 parts gold per 1,000.
Weight and purity together set the gold content. The BIS hallmarking scheme covers seven gold grades, from 9K (375 fineness) to 24KS (995), and every hallmark carries the BIS mark, the purity and a six-digit HUID. The table works out the fine gold in a 10 g article at each grade's minimum fineness.
| Hallmark grade | Minimum fineness (parts per 1,000) | Fine gold in a 10 g article |
|---|---|---|
| 24KS | 995 | 9.95 g |
| 22K | 916 | 9.16 g |
| 20K | 833 | 8.33 g |
| 18K | 750 | 7.50 g |
| 14K | 585 | 5.85 g |
| 9K | 375 | 3.75 g |
Purity claims are tied to weight in law as well. If hallmarked jewellery tests below its marked purity, the BIS consumer protection rules entitle the buyer to twice the difference, calculated on the weight of the article sold, plus testing charges.
Counter features worth paying for
- Displays on both sides. The Ace JS-6002, JS-600 and JS-10KG show the weight at the front and the back, so the customer reads the same number as the jeweller.
- A cover or windshield. Moving air pushes the last digit around. The NIST good measurement practice on weighing lists air currents and temperature differences among the main sources of weighing error. The JS-6002 has a clear cover, and the 0.001 g balances have glass windshields.
- Battery backup. The JS-6002, JS-600 and JS-10KG run on an adapter and an inbuilt battery, so billing continues through a power cut.
- Level indicator. The JS-600 and the CS-2002 have a level indicator for setting the scale flat.
- Tare and piece counting. Tare clears a tray or paper; piece counting counts beads, stones and findings from a sample.
- Stainless steel pan. The 600 g counter models use a 130 mm round steel pan.
Omace gives a working range of 10 °C to 40 °C for the JS-600 and JS-10KG. Keep any jewellery scale away from fans, AC vents and open windows.
How to check and calibrate a jewellery scale
- Set it up once. Use a firm, level table away from fans and AC vents. Moving a scale to a new table can change the reading, so recheck it after every move.
- Let things reach room temperature. NIST reports errors as large as 0.2 mg on 20 g weights when they were 4 °C warmer or cooler than the balance. Keep the test weight beside the scale before you use it.
- Exercise the scale. NIST advises placing and removing a load several times before taking readings, because repeatability improves once the balance has warmed up.
- Handle small weights with tweezers or gloves. NIST says small weights should never be touched by hand, since skin leaves oil on them.
- Use the right class of weight. OIML R 111 names Class F2 weights for important commercial transactions, such as precious metals and stones, on Class II scales, and Class F1 for Class I and II scales. A 200 g F1 weight is within ±1.0 mg and a 200 g F2 weight within ±3.0 mg.
- Calibrate only when the check fails. The Ace JS-6002 is calibrated manually. Switch it fully off once and back on, press and hold the TARE key for about 5 seconds to open calibration mode, and place the weight the display asks for, which differs by model. A scale that has been stamped for trade is sealed, so only a registered repairer may recalibrate it.
R 76 requires a test weight's error to be no more than one third of the scale's permitted error. On a Class II scale with e = 0.01 g, that limit is about 3.3 mg at 200 g, which a 200 g Class F2 weight meets. The step-by-step guide on how to calibrate a gold weighing scale covers the calibration mode itself.
Buying a jewellery scale from Omace
Omace Brands Private Limited has made and supplied weighing scales in India since 1994, from Bagru, Jaipur, and sells its jewellery and precision scales under the Ace brand. Every scale is checked before dispatch, and scales bought from the Omace store carry a 2-year warranty on manufacturing defects, excluding batteries and physical damage. Omace delivers PAN India. Omace scales are made in India. As a manufacturer, Omace Brands Private Limited holds ISO 9001:2015, ISO 13485:2016 and EU MDR quality certificates, and CE and US FDA compliance certificates; each is listed with its certificate number on the Omace certificates page.
Jewellery brands and distributors can sell Ace models under their own name through private label manufacturing. More about Omace.
