That is true: there are bigger diamonds in that bracelet from the De Bijenkorf Department Store. But there are more diamonds in the Tutti Frutti bracelet. So my estimation of € 15.000,-- for the diamonds alone, while having no idea for the whole bracelet with all gemstones, is not too overdone.
I think Máxima had a bargain actually with her € 25.000,-- for a bracelet. Look at these auction results at Christie's:
US $ 1,753,313.-- (sale 1400, lot 285)
US $ 1,070,275.-- (sale 1397 / lot 223)
US $ 962,500.-- (sale 2472 / lot 333)
This was the cheapest one at Christie's, but with very spare diamonds: