I'm going to try increasing the concentration. Here they told me that pieces of the stone can be found in esoteric shops, I'll stop by anytime to see if it's true.
Thanks for stopping by and commenting dear @felixmarranz . A big hug from Maracay.
You might find better prices at Arab grocery stores or in stores that sell spices and condiments; a visit to the free market might be another option.
(aqui le dejo un resultado de mi busqueda, pero hay más: https://articulo.mercadolibre.com.ve/MLV-717648669-piedra-alumbre-1kg-_JM#polycard_client=search-nordic&position=5&search_layout=grid&type=item&tracking_id=3211d9b6-ec57-4733-a1ed-48de5a48e261)
Health and blessings