ComproDiamanti.it · by La Diamanteria
Sell your diamond to people who truly know diamonds
We buy diamonds directly from private sellers, valuable gems and important jewellery. Free valuation, without auctions or intermediaries. Milan, since 2009.
by La Diamanteria
Via Vincenzo Monti 47, Milan
Since 2009 · direct buyer
Traceable bank transfer
Five generations of Diamantaires
Gemological assessment
Recognised reports: GIA / HRD / IGI
What we buy
Diamonds
Natural diamonds from 1 ct per stone, with GIA, HRD or IGI reports or no report.
Request a quoteDiamond jewellery
Solitaires and multi-stone jewellery, each with a dedicated assessment path.
Request a quoteVintage and signed jewellery
Rare pieces, with particular attention to gemstone quality.
Request a quoteHow it works
Request a valuation
Send the form or message us on WhatsApp, with photos and reports if available.
Professional assessment
A gemmologist reviews your request and arranges an appointment if needed.
Direct offer
La Diamanteria makes its own offer, without auctions or intermediaries.
Payment
If you accept, payment is made by traceable bank transfer.
Why sell to us
Direct buyer
The offer comes from us, not an intermediary.
Five generations of Diamantaires
A documented family history in the diamond trade.
Gemological assessment
We examine the stone's characteristics and available documentation.
Milan premises
Appointment at Via Vincenzo Monti 47 and payment by traceable bank transfer.
We buy directly
ComproDiamanti.it is La Diamanteria's direct-buying service. We do not auction your diamond or offer it to a network of buyers. If it meets our criteria, we make the offer ourselves.
One point of contact, a more straightforward process.
Our premises at Via Vincenzo Monti 47, Milan
ComproDiamanti.it is run by La Diamanteria at Via Vincenzo Monti 47, Milan.
A physical location, one direct point of contact, a professional assessment.
Main criteria
Natural diamonds from 1 ct per stone, with GIA/HRD/IGI or no certificate. We do not buy lab-grown diamonds or stones with AIG, GRA, GWLAB or ALGT reports. Watches are limited to selected brands; rubies, sapphires and emeralds can be under 2 ct.
All criteriaGoogle reviews
Read our clients' experiences
Reviews are published directly on our Google profile. If you've worked with us, your feedback helps others decide who to trust with a diamond.
Frequently asked questions
I want to sell my diamond ring: who should I contact?+
A specialist diamond buyer. La Diamanteria has bought directly from private sellers in Milan since 2009: we assess the stone gemologically and, if it meets our criteria, make our own offer without auctions or intermediaries.
Which diamonds do you buy?+
We assess natural diamonds from 1 carat per single stone, with a GIA, HRD or IGI certificate or without a certificate. We do not buy lab-grown diamonds or diamonds graded by AIG, GRA, GWLAB or ALGT. We also assess rubies, sapphires and emeralds under 2 carats.
How quickly will I get a first valuation?+
For an immediate valuation, message us on WhatsApp or call +39 02 466891. You can also fill in the online quote form: one of our gemmologists will review your request, and the final offer follows an in-person examination of the stone.
How is a diamond's value calculated?+
Price depends on the 4Cs: carat weight, colour, clarity and cut, plus fluorescence, proportions and an international certificate. We reference live prices from the Antwerp, Tel Aviv, New York, Dubai and Mumbai bourses.
Guides & insights
20 September 2026
How to sell a diamond ring: the complete guide
Useful documents, assessment criteria and steps for selling a diamond ring directly to a buyer.
Read10 September 2026
GIA, HRD and IGI certificates: why they matter when you sell
Not all certificates carry the same weight. Here are the internationally recognised ones.
Read28 August 2026
How much is a 1 carat diamond worth?
Colour, clarity and cut can change the price of a 1 carat diamond many times over.
Read