Assertion: fountain pen's ink | /r/ObjectUse | used in fountain pens
Facets:
Source sentences:
text: Water-based inks used in fountain pens can fade over time are less likely to adhere to other types of surfaces.
text: The inks used in fountain pens are water-based, but there are many different kinds and qualities.
text: The water-based ink used in fountain pens allows a smoothness of writing unlike any other writing instrument.