selenite

Definition

A soft, glassy form of gypsum (chemical formula CaSO₄·2H₂O).

Etymology

From Ancient Greek σελήνη (selḗnē, “moon”) + -ite; the chemistry sense comes via the name of the element selenium.

Example Sentences

• "I followed them to my study, and found lying on my writing-table still, with the selenite paper-weight upon it, the sheet of work I had left on the afternoon of the opening of the cylinder."
• "Glass windows replaced the old tiny windows of selenite (crystallized gypsum), and stovepipe replaced adobe chimneys."