Stack of Stones (Stapel van Stenen)

18-03: Lecture 'Gem or Scam?' for LVGA Friesland
2026-03-18 20:00 - 22:00 (Europe/Amsterdam) | Natuurmuseum Fryslân, Schoenmakersperk 2, Leeuwarden, 8911 EM, Netherlands
During the meeting on March 18, 2026, I will give a lecture on “Gem or Scam?” for the Frisian division of the national geological association LVGA in Leeuwarden (NL).
In today’s gem & mineral market, numerous gemstones, minerals and rocks are sold under commercial or fanciful names. In addition, more and more man-made or treated materials are circulating for which misleading designations are used. For collectors and enthusiasts, it is often far from clear what kind of stone it really is, geologically speaking.
In this lecture, you will gain practical insights into how to recognize such “scammite”. Using concrete examples and recent developments in the market, we will discuss trends in treatments, syntheses and naming. Of course, you will be given tips on how, as a collector or enthusiast, to look at stones in the trade with a critical eye.
New: because the physical book “Belazeriet of niet?” is now sold out, I will give a demonstration of the online Gem or Scam Library during the evening. This comprehensive, up-to-date resource offers insight into numerous trade names and treatments, and is available to interested parties as an online subscription.
Before and after the lecture and during the break there will be an opportunity to view examples of Scammite as well as to make an online library subscription. Do you have a special example of your own or are you unsure about a stone? Feel free to bring it along – we’d love to look at it together!
For more information about the LVGA division Friesland, I refer you to their website.
The Natural History Museum Fryslân in Leeuwarden is open from 7:30 p.m. Address: Schoenmakersperk 2 , 8911 EM Leeuwarden (NL).
Ample parking is available in the Hoeksterend parking garage, approximately 500 m away.

11-10: Lecture 'Gem or Scam?' for Geolithos
2025-10-11 15:00 - 17:00 | Evenementenhal Den Dijk, Rozenkransweg 4, Zonhoven, 3520, Belgium
During a meeting of the Belgian geological society Geolithos on Oct. 11, 2025, I will give a lecture on “Gem or Scam?” at Evenementenhal Den Dijk in Zonhoven (Hasselt, BE).

In today’s gem & mineral market, numerous gemstones, minerals and rocks are sold under commercial or fanciful names. In addition, more and more man-made or treated materials are circulating for which misleading designations are used. For collectors and enthusiasts, it is often far from clear what kind of stone it really is, geologically speaking.

In this lecture, you will gain practical insights into how to recognize such “scammite”. Using concrete examples and recent developments in the market, we will discuss trends in treatments, syntheses and naming. Of course, you will be given tips on how, as a collector or enthusiast, to look at stones in the trade with a critical eye.

New: because the physical book “Belazeriet of niet?” is now sold out, I will give a demonstration of the online Gem or Scam Library during the evening. This comprehensive, up-to-date resource offers insight into numerous trade names and treatments, and is available to interested parties as an online subscription.

Before and after the lecture and during the break there will be an opportunity to view examples of Scammite as well as to make an online library subscription. Do you have a special example of your own or are you unsure about a stone? Feel free to bring it along – we’d love to look at it together!

For more info on GVL Geolithos and their activities, I refer to their website and Facebook page.

04/05-10: International mineral show Rijswijk
2025-10-04 10:00 - 2025-10-05 17:00 | De Broodfabriek Volmerlaan 12 2288 GD Rijswijk, Volmerlaan 12, Rijswijk, 2288 GD, Nederland
During the show on October 4 and 5, at the booth i01 of Stapel van Stenen (Stack of Stones) and Henk Rijneveld FGA (gemologist) you can have your newly purchased mineral/precious stone checked. But of course you can also bring a stone or jewel from home that you don’t know the name of (anymore).
A short determination is completely free, we do have a maximum of 2 pieces per person. If you want a full authenticity examination or want to have more stones identified, this will take more time. You can make arrangements for this at the show with the relevant expert.
During the show you can also learn more about the Gem or Scam Library, (online) courses, community and advice for collectors, stores and web shops in our booth.
Buy your tickets in advance to bypass the queue!
Listen to the podcast beforehand and/or read the article with tips on visiting a mineral show!

17-9: Lecture 'Gem or Scam?' for Geode Zwijndrecht
2025-09-17 20:00 - 22:00 | Geode Zwijndrecht: Develsteincollege, Develsingel 5, Zwijndrecht, 3333LD, Netherlands
During the club meeting of Sept. 17, 2025, I will give a lecture on “Gem or Scam?” for Geode Geological Society in Zwijndrecht (NL).
In today’s gem & mineral market, numerous gemstones, minerals and rocks are sold under commercial or fanciful names. In addition, more and more man-made or treated materials are circulating for which misleading designations are used. For collectors and enthusiasts, it is often far from clear what kind of stone it really is, geologically speaking.
In this lecture, you will gain practical insights into how to recognize such “scammite”. Using concrete examples and recent developments in the market, we will discuss trends in treatments, syntheses and naming. Of course, you will be given tips on how, as a collector or enthusiast, to look at stones in the trade with a critical eye.
New: because the physical book “Belazeriet of niet?” is now sold out, I will give a demonstration of the online Gem or Scam Library during the evening. This comprehensive, up-to-date resource offers insight into numerous trade names and treatments, and is available to interested parties as an online subscription.
Before and after the lecture and during the break there will be an opportunity to view examples of Scammite as well as to make an online library subscription. Do you have a special example of your own or are you unsure about a stone? Feel free to bring it along – we’d love to look at it together!

For more info on Geode Zwijndrecht and their activities, I refer you to their website and Facebook page.
