How do I identify opaline glass?

To identify opaline glass, try holding it up to a natural light source. Most pieces will appear semi-translucent and have a pinkish-red tint when viewed in the sun. Next, search for seam marks. By the 19th century, artisans used a free-blowing technique to produce opaline glass, so most pieces are free of seams. You'll also usually see a pontil on the mark, which forms when the glass is broken off during the production process. Maker's marks can also provide a clue, as some makers are especially well-known for opaline glass. Among them are Baccarat, Lalique, Saint-Louis, Le Creusot, Portieux Vallerystahl and Loren Hope. If you're still unsure whether your piece is opaline, consult a certified appraiser or experienced antique dealer. Explore a range of opaline glass objects on 1stDibs.