450,000 diamonds at Mennica: Nivoda wholesale integration and metal prices driven by spot rates
Mennica Sądecka sells gold, silver, platinum and palladium as coins and bars, along with diamonds and gemstones. We built a PrestaShop store for the company that pulls hundreds of thousands of stones from the Nivoda wholesaler every day, converts their prices into Polish zloty and updates stock. Prices of coins and bars move with the metal rate, taking into account how much of the metal the product actually contains.
In short
- Challenge: selling over half a million products online whose prices change daily, and for metals even during the day.
- Diamonds: a daily import from the Nivoda wholesaler: new stones, prices converted from dollars to zloty and current stock.
- Metals: the price of every coin and bar follows the current rate, the weight and the fineness of the metal.
- Catalog: filters based on certificate parameters, search and speed optimization for such a large offer.
About the client: Mennica Sądecka
Mennica Sądecka is a precious metals dealer with branches in Nowy Sącz and Kraków, Poland. It sells gold and silver bullion coins, bars of gold, silver, platinum and palladium, buys metals back, and has recently added natural and lab-grown diamonds as well as colored gemstones. Customers can buy online with delivery or collect their order at one of the branches.
The challenge: an offer that cannot be managed by hand
In this business a price stays valid for a very short time. The gold or silver rate changes during the day, and every diamond is one of a kind: it has its own certificate, a price in dollars, and can be sold at any moment somewhere in the world. With hundreds of thousands of stones and hundreds of coins and bars, updating prices and availability by hand was out of the question.
Without automation
- Metal prices corrected by hand after a rate change
- Diamonds priced one by one, on request
- The risk of selling a stone the wholesaler no longer has
- An offer limited to what is in the branch
- Stone parameters retyped from certificates
After the launch
- Coin and bar prices follow the metal rate
- Every diamond has a price in zloty right away
- Stock updated daily, sold stones disappear from the offer
- Over 450,000 diamonds available to order
- Certificate parameters feed the filters automatically
Nivoda wholesale integration: a fresh catalog every day
Nivoda is an international wholesaler of diamonds and gemstones used by jewelers around the world. The Mennica store downloads its full offer every day and turns it into PrestaShop products: with a name, parameters, price, stock and video.
New stones every day
The import adds stones that have appeared at the wholesaler and updates those already in the store. The catalog reflects what can actually be ordered.
Prices converted to zloty
The wholesaler quotes prices in dollars. The store converts them at the current USD/PLN rate and adds a margin, so the customer immediately sees the final price in zloty.
Current stock levels
A stone sold at the wholesaler disappears from the store at the next update. This limits cases where a customer orders something that is no longer available.
Parameters straight from the certificate
Carat weight, color, clarity, cut, fluorescence and the GIA, IGI or HRD certificate number are saved as product features, together with a 360° view of the stone.
What goes into the catalog
Stones from the wholesaler are split into separate “to order” categories. Next to them there are “available now” categories with stones physically held in Mennica’s branches.
| Store category | Number of stones |
|---|---|
| Diamonds to order (natural) | over 255,000 |
| Lab-grown diamonds to order | over 218,000 |
| Fancy color diamonds to order | approx. 11,800 |
| Lab-grown fancy color diamonds to order | approx. 10,400 |
| Colored gemstones to order | approx. 8,800 |
As of November 2026. The numbers change daily with the wholesaler’s offer.
Half a million products in one store
A catalog of this size is a challenge of its own. In a few clicks the customer has to go from hundreds of thousands of stones down to the few that matter, and the store has to stay fast.
Filters based on diamond parameters
Cut, weight, clarity, color, cut grade, certificate and price. Each value shows the number of stones, so the customer knows how many remain after narrowing down.
Search that leads to a category
A general query, for example for a diamond of a given cut, opens the right category with filters applied instead of a long list of results.
Speed despite the scale
After optimization the home page response time dropped from about 2 seconds to about 0.5 seconds, and the category with over 250,000 diamonds opens several times faster than before.
A clear delivery time
Every product shows whether it is available now in Kraków or Nowy Sącz, or brought in to order and how long that takes.
Metal prices driven by rates and metal content
The other part of the offer is precious metals: coins and bars of gold, silver, platinum and palladium. The store continuously downloads the rates of these four metals in zloty and calculates the price of every product from them. Not only the weight matters but also the fineness, that is how much pure metal the coin or bar actually contains.
metal rate × weight × fineness, plus the product margin
Example: a coin of .900 fineness contains 90% pure gold, so its base price is 90% of the value of gold of the same weight. A bar of .999 fineness is priced as pure metal.
Four rates, continuously updated
Gold, silver, platinum and palladium. When a rate changes, the prices of all products made of that metal change with it, without any staff involvement.
Fineness and weight of the product
The system knows the weight and fineness of every coin and bar. The price follows the amount of pure metal, not just the weight of the product.
Selling price and buyback price
Next to the selling price the customer sees the price at which Mennica will buy the same product back. Both values update with the rate.
Margin and minimum price
Each product has its own percentage or fixed margin and a minimum price the system will not go below, even when the rate moves sharply.
What else the store offers
Beyond the integrations, the store has several features driven by the nature of the business: a buyer wants to be sure what exactly they are buying, when they will get it and how much they can later sell it for.
- A diamond page with the certificate number and links for verification at the GIA, IGI and HRD laboratories
- Availability by branch: Kraków and Nowy Sącz, with shipping within 24 hours
- Delivery times for coins and bars updated from the metal supplier’s data
- A buyback section: scrap gold, silver and platinum, and buyback by post
- Coins and bars filtered by country, fineness, weight and condition
- A wishlist, an investment blog and a mobile version of the whole catalog
What it delivers for Mennica and its customers
A huge offer without a warehouse
Over 450,000 diamonds on sale without tying up capital in stock. A stone is brought in only after it is ordered.
Prices always in line with the market
Mennica does not sell below value after a rate increase and does not put customers off with an outdated price after a drop.
No manual updates
The team does not retype price lists or certificates. It takes care of customers, not a spreadsheet.
Customers know what they are buying
The certificate, parameters, delivery time and buyback price are visible before the purchase, which builds trust in this business.
Scope of work
- An online store on PrestaShop
- Integration with the Nivoda diamond wholesaler: import, prices, stock
- Converting stone prices from USD to PLN with a margin
- Automatic pricing of coins and bars from the rates of four metals
- Buyback prices shown with products
- Filters and search for a catalog of over 500,000 products
- Store speed optimization
- Ongoing technical support and development
Does your offer change faster than you can update it?
We will connect your store to a wholesaler, exchange rates or market quotes so that prices and stock update on their own. See how we approach integrations and automation.