Like a diamond, the dataset behind the diamond workers website contains many facets. The aim of this data story is to show how these facets can be explored through SPARQL queries. Those not familiar to SPARQL can simply look at the results of the queries as they are presented on this page. But a little SPARQL knowledge can take you much further than that: just click on Try this query yourself and modify the query as you like. Don't worry, you will not break anything!


Diamond workers learned their skills by working as an apprentice in one of the diamond factories. This apprenticeship was part of a formal education and was monitored by a master. After a successful examination most of the students moved on to become a union member in one of the Diamond Worker Unions, like the ANDB. The apprentice registration cards from Amsterdam are held at the IISH. They hold a lot of information on the lives of the young diamond workers.

One of these apprentices was Andries Gerritse, born in 1890, started his training as brilliant polisher in 1904, together with 295 other students.

The query below shows us the apprentices per occupation per year. You can adapt the value of both.

Parents in the diamond industry

From the apprentice cards we can discover that many students had a parent who was also a diamond worker, often within the same profession.

Andries father Tobias Gerritse was a brilliant polisher, his son was also trained to become a brilliant polisher. From the master field, we can deduct he was probably trained by his own father.

Enter the first and/or lastname of the apprentice in the query below and see if you find a matching parent as master.

This diagram shows the number of apprentices with a parent with the same occupation, another specialisation or another trade altogether:

Parents in the diamond industry

Brothers and sisters

Often more children from one family were trained to become diamond workers. Card numbers of brothers and sisters where noted on their apprentice cards. With this information we can try to connect these siblings.

Andries had a brother Abraham Gerritse who was also trained as a brilliant cutter.

Enter the first and/or lastname of the apprentice in the query below and see if you find a brother or sister.

This diagram shows the number of apprentices with a brother or sister in ANDB:

Siblings in the diamond industry

Formal education

Students in the diamond industry where trained as an apprentice in a diamond factory. Here they learned the skills required in their future profession. Between 1895 and 1910 more than half of the students where trained to become brilliant polishers. Andries Gerritse was one of them.

Apprentice specializations between 1895 and 1910

Later this division changed and less brilliant polishers, but more brilliant cutters were trained:

Apprentices specializations between 1910 and 1940


Apprentice diamond workers were trained on the job. The diamond factories or workshops where this training took place were spread all over Amsterdam. The diamond workers website provides a map with their locations. A question this map does not answer is wether the apprentices lived near their workplace. A SPARQL query shows that this is not always the case.

This query shows the location of the Ed. van Dam diamond workshop combined with the (first) adresses of the apprentices that had their training at this workshop. It is possible to change the name of the workshop to see if you get different results.

  • red: the workshop
  • orange: male apprentices
  • green: female apprentices

The markers are clickable and contain a link to the linked data about the apprentice.

ANDB Members

The registration of the ANDB members was done by membership cards. The cards held personal information and mutations in the memberships. Many members had more than one card in their career as a diamond worker. The simple search query below is set up to search for persons by (part of) their name and get an overview of all cards matching to their id's.

Andries Gerritse had two membership cards. From 1922 to 1939 he lived and worked in Antwerp. When he returned in 1939 he joined the ANDB again and received a new membership card.


The section numbers on the ANDB membership cards provide information on the professions of the the diamond workers. The division between the different specialisations matches quite well with that of the students above.

Andries Gerritse was trained as a brilliant polisher and it's no surprise he also worked in that profession.

This diagram shows the number of ANDB members per specialisation per year. You can enter another year:

Diamond workers occupations

Places were diamond workers lived

The ANDB and ADB cards hold a lot of information on the residence addresses of the diamond workers. These were not only in Amsterdam or Antwerp. This table shows the number of diamond workers that at one point during their union membership were registered in a certain place.

Streets where diamond workers lived

Through time some streets have been populated by many diamond workers, especially in Amsterdam. Here's an overview of all streets, ordered by the frequency they appear on the cards: