I have been wondering too. He/she has written many articles about the Dutch royal jewels and suggests to have intimate knowledge, for instance about how the jewels are kept and have been registered. But from time to time his/her information turns out to be incorrect, like for instance about the large sapphire parure of which he/she stated that is was created by Mellerio. I also think that the name is a "nom de plume".
--Previous Message-- : Just a question; I'm sure it's a pseudonym. :