A relative once walked out of a Bengaluru jewellery store with a “diamond” pendant, thrilled about the deal she had scored. Three months later, she found out the stone was a diamond simulant — visually similar, chemically nothing alike, and worth a fraction of what she paid. The jeweller had not technically lied; she simply had not asked the right questions.
That story is more common than it should be in 2026. The Indian diamond jewellery market has grown dramatically, with lab-grown diamonds making quality pieces accessible to buyers who previously couldn’t justify the spend. But alongside genuine innovation, there is also more confusion, more creative pricing, and more ways to walk away from a purchase feeling cheated. The good news is that armed with 20 specific questions, you can evaluate any jeweller — online or offline — with enough confidence to buy right the first time.
Carry this list. Use it. Most sellers who stock genuinely good product will welcome the questions.
Certification and Grading
1. Is the diamond certified, and by which laboratory?
This is the first question, and the answer tells you a lot. The two laboratories that matter for Indian buyers are IGI (International Gemological Institute) and GIA (Gemological Institute of America). Both issue independent grading reports that assess cut, colour, clarity, and carat weight. An uncertified diamond — even if the jeweller swears by its quality — cannot be independently verified. Walk away or ask for a significant price reduction if certification is absent.
For lab-grown diamonds specifically, IGI has become the industry standard in India. If you want to understand why that matters, the detailed breakdown in IGI-Certified Engagement Rings in India: Why Certification Matters in 2026 is worth reading before you shop.
2. Can I see the actual grading report, not just a summary card?
Jewellers sometimes display a certificate “summary” — a small card or sticker with a few numbers. The full grading report runs multiple pages and includes a plot diagram of inclusions, exact measurements, and the grading laboratory’s unique report number. Ask to see the full document. Then verify it: IGI’s website lets you enter the report number and confirm authenticity in under a minute.
3. What are the exact 4Cs — and what do the grades actually mean for this specific stone?
Colour grading runs from D (colourless) to Z (light yellow). Clarity runs from FL (flawless) to I3 (heavily included). Cut grades range from Excellent to Poor. Carat is weight, not size — two stones of identical carat weight can look dramatically different depending on cut proportions. Ask the jeweller to explain where each grade sits on the scale and what the practical visual difference is. A good jeweller will explain it without pressure. A jeweller who rushes past this question is worth treating with caution.
4. For lab-grown diamonds: is this CVD or HPHT, and does it matter for this purchase?
Lab-grown diamonds are created via two methods — Chemical Vapour Deposition (CVD) or High Pressure High Temperature (HPHT). Both produce real diamonds with identical physical and chemical properties to natural diamonds. The method affects neither durability nor brilliance in any meaningful day-to-day sense, but some buyers prefer to know. What matters more is the grade. A poorly cut CVD stone is worse than a well-cut HPHT stone, and vice versa.
Pricing and Value
5. How is the price broken down — stone cost versus making charges versus gold cost?
This is where most overpayments happen. Jewellery pricing in India typically has three components: the cost of the diamond(s), the cost of the gold setting (usually priced by weight at that day’s gold rate), and making charges. Making charges can range from 8% to 25% of gold value depending on the piece and the retailer. Ask for each component separately. If a jeweller cannot or will not give you this breakdown, that is your answer.
6. Is this a lab-grown or natural diamond, and what is the price difference for this specific piece?
Lab-grown diamonds are chemically and physically identical to natural diamonds but cost roughly 70–80% less at comparable quality grades. At brands like ONYA, lab-grown diamond pieces are priced at approximately 20% of what equivalent natural diamond jewellery would cost. That gap is real and documented. If a seller is offering “lab-grown” diamonds at prices close to natural diamond rates, ask them to justify the pricing.
For a thorough look at how the pricing compares in practice, Lab Grown Diamond Prices vs Natural: Market Analysis 2026 lays out the numbers honestly.
7. Are there any hidden charges — GST, shipping, insurance, or packaging fees?
The quoted price is often not the final price. GST on jewellery in India is 3%. Online orders may carry shipping charges unless explicitly waived. Some stores add insurance or certification fees at checkout. Ask upfront: “Is this the final price I pay, door to door?” You want a yes or a specific list of additions, not a vague “we’ll calculate it at billing.”
8. How does your pricing compare to market rates for the same grade stone?
A reasonable jeweller will be able to tell you how they’ve priced the stone relative to prevailing market rates. If they cannot, or if the price seems significantly higher than comparable certified stones you’ve seen elsewhere, that is worth probing. Checking two or three online and offline quotes for similar specs (same carat weight, similar colour and clarity grades) takes an hour and can save thousands of rupees.
Hallmarking and Metal Quality
9. Is the gold hallmarked, and what does BIS hallmarking guarantee?
BIS (Bureau of Indian Standards) hallmarking is mandatory in India for gold jewellery and guarantees the metal purity. A 18KT piece should bear the BIS hallmark, the purity mark (750 for 18K), and the jeweller’s HUID (Hallmark Unique Identification number). This is not optional. If a piece lacks BIS hallmarking, you have no independent verification of the gold’s purity.
10. What karat gold is used in the setting, and why?
Most diamond jewellery is set in 18K gold (75% gold, 25% alloy) because it strikes the right balance between durability and value. 22K gold, traditional for Indian jewellery, is too soft for diamond settings. Some sellers offer 14K settings at lower price points. Ask which karat is used and confirm it matches the hallmark. If the jeweller says 18K but the hallmark shows something else, that is a problem.
Buyback, Exchange, and After-Sales Policies
11. What is your buyback policy, and what percentage of today’s value will I receive?
Buyback policies vary enormously. Some stores offer 0% buyback — you simply cannot sell the piece back to them. Others offer 50–60% of current market value. ONYA offers an 80% buyback policy, which sits well above the industry average. Ask for the specific percentage, confirm whether it applies to the stone and the gold or just one component, and ask if the policy is written anywhere you can reference.
12. What is your exchange policy, and are there conditions attached?
Exchange policies — trading in an existing piece for a new one — are more generous at most stores than outright buyback. But conditions vary: some require the original certificate, some deduct making charges, some apply only within a certain timeframe. Ask about the lifetime exchange policy specifically. At ONYA, the 100% lifetime exchange policy means the full value of a purchased piece can be exchanged toward a new one, without time limits.
13. Is there a warranty, and what does it cover?
Warranties on jewellery typically cover manufacturing defects — a prong that breaks within the first year, a clasp that fails prematurely. They rarely cover accidental damage. Ask what specifically is covered, for how long, and whether repairs under warranty are free. Also ask about routine maintenance: do they offer free prong checking, rhodium plating on white gold, or cleaning?
Product-Specific Questions
14. For a solitaire: what is the cut grade, and how does it affect the diamond’s brilliance?
Cut is the most important of the 4Cs for visual impact. An Excellent or Ideal cut stone will return light to your eye far more effectively than a Good or Fair cut stone of identical carat weight. Many buyers fixate on carat size while overlooking cut grade. A well-cut 0.7 carat stone can outshine a poorly-cut 1 carat stone. Ask specifically about the cut grade and ask the jeweller to show you the difference under a loupe if possible.
15. For a mangalsutra or everyday piece: how durable is this for daily wear?
Not all diamond jewellery is designed for daily wear. Some intricate settings — particularly pavé or channel-set designs — are more vulnerable to daily knocks. If you’re buying a mangalsutra, pendant, or bracelet you intend to wear every day, ask about the prong or bezel construction, whether the setting is reinforced, and whether the jeweller recommends the specific design for daily wear. A good jeweller will be honest about this even if it steers you toward a simpler design.
16. For a ring: can it be resized, and is that included?
Resizing a ring after purchase is common — fingers change with seasons, weight changes, and the right size on the day of purchase can shift over years. Some rings, particularly those with stones running the full circumference (eternity bands), cannot be resized. Ask upfront. If resizing is possible, ask whether the first resize is complimentary.
Ethical and Environmental Questions
17. For lab-grown diamonds: where is the stone grown, and can you provide any supply chain documentation?
Lab-grown diamonds sidestep the ethical concerns around conflict diamonds and the significant environmental footprint of mining. But “lab-grown” is a broad category — some labs use renewable energy, others don’t. If ethical sourcing matters to you, ask whether the seller can provide any documentation about the growing facility. This question is increasingly relevant to buyers who want the full picture on sustainability, as explored in How to Buy Ethical Diamond Jewellery in Bangalore: Expert Tips.
18. For natural diamonds: do you follow Kimberley Process compliance?
If you’re buying a natural diamond, the Kimberley Process Certification Scheme (KPCS) is the international standard designed to prevent conflict diamonds from entering the supply chain. Any reputable seller of natural diamonds should be able to confirm compliance without hesitation.
The Final Two
19. Can I get all policies in writing before I pay?
Verbal assurances are worth little if a dispute arises later. Buyback percentages, exchange terms, warranty coverage, resize commitments — ask for these in writing, either as a printed policy document or a clear notation on your receipt. Most legitimate jewellers will oblige. A seller who resists documentation of the policies they’re verbally offering is telling you something important.
20. What happens if the piece I receive does not match the grading report I was shown?
This is the question that separates confident buyers from uncertain ones. Ask the jeweller: if I receive the piece and take it to an independent gemologist, and the stone does not match the grades on this certificate, what is your resolution process? A seller who stocks certified product will answer this without flinching. The answer should include replacement, full refund, or independent arbitration — not “that won’t happen.”
A Printable Quick-Reference Version
Before you walk into any store or finalise any online purchase, run through these five minimum checks as a baseline:
- Does the diamond have an IGI or GIA certificate you can verify online?
- Is the gold BIS hallmarked with an HUID?
- Has the price been broken down into stone, gold, and making charges separately?
- Is there a written buyback and exchange policy?
- Have you cross-checked the specs and price against at least one other seller?
If all five check out, you’re starting from a reasonable position. The remaining 15 questions let you go deeper depending on the piece and the purchase value.
The diamond jewellery market in India in 2026 has genuinely good options — certified lab-grown brands with transparent pricing, legitimate buyback commitments, and quality standards that rival what was only available at the top end a decade ago. The challenge is not finding quality; it’s knowing how to identify it. These questions are that identification process, made portable.
For buyers in Bengaluru specifically, the practical comparison of brands and their actual policies is covered in detail in the ONYA vs Other Lab-Grown Diamond Brands in Bengaluru: A Detailed Comparison — worth checking before you make your shortlist.
