It is somewhat porous, brittle and not malliable but can be machined so I would guess it could be engraved. Doublt it would look good but one could sure make a test to see.
Cast Iron can be engraved but results will depend on the density of the metal. I've been engraving Stanley hand planes for years and they are cast. I've run into some brittle ones but most have been ok. A little funky to work with but doable.
Layne
yes. having said that, virtually every piece i ever engraved (most were tools) cut rather crumbly (sugar cube effect), but most all would engrave. i'd not have high hopes for the quality of your project, regardless of the skill level applied to such.