Lexitechnia

Pliny on the stone of Siphnos (Naturalis Historia 36.44):

In Siphnos lapis est, qui cavatur tornaturque in vasa vel coquendis cibis utilia vel ad esculentorum usus, quod et in Comensi Italiæ lapide viridi accidere scimus, sed in Siphnio singulare quod excalfactus oleo nigrescit durescitque natura mollissimus; tanta qualitatum differentia est.

In Siphnos there is a stone which is hollowed out and lathed into vessels or utensils either for cooking food or for serving foodstuffs, which we know also happens with the green stone of Comum, Italy, but it is something unusual in the Siphnian that, though by nature it is quite soft, it blackens and hardens when it has been heated with oil; such is the difference in their qualities.

The stone described is generally taken to be soapstone or steatite, which is a very soft kind of stone (consisting chiefly of talc) still used today in kitchen counters and cookware, and which is often treated with oil for a darker color and to reduce the appearance of scratches. This use also gave the stone the (apparently medieval) name of lapis ollaris “potstone.”

Siphnos (still called Σίφνος Sifnos today) is one of the islands in the Cyclades, Greece. Besides its quarries, it was also known for its gold and silver mines, all of which, according to legend, were inundated by Apollo when they tried to pass off a gilded offering to the god as the golden one they habitually pledged.

[For qualitas.]