If you've ever seen an opaque piece of antique glass that looks like it glows from the inside, it's probably opaline and it probably originated in France.
What is Opaline Glass?
Opaline glass is opaque glass or crystal. It can be white or colored. Inspired by milk glass of 1500's Venice and the opaque white glass of 1700's Bristol England, the French decided to put their spin on this glass art, beginning in the 1800's. And what a spin it was. France produced arguably some of the best opaline glass in history.
The Main Producers
Creusot, Baccarat, and Saint-Louis were the main producers of French Opaline Glass in its beginnings.
The first colors produced were in homage to the bright colors of Bohemian glass. They included turquoise blue, pink, and yellow. Pink, however was only produced from the early to mid 1800's. It was made of crystal, semicrystal, glass, and pâte-de-riz (glass made by firing glass powder in a mold).
Opaline Glass Colors
Sky blue, a creation of Bohemian glass makers in 1835, was copied at Baccarat and Saint-Louis c 1843.
Ultramarine blue was most frequently used between 1845 and 1850.
Some bicolour (white and blue) opaline was made at Baccarat in 1850. Purple and greens were also produced in the mid part of the 1800's.
Collecting French Opaline Glass
As with most antique collectibles, the first rule is: collect what you love. If you collect pieces that catch your eye and that you enjoy, you can't go wrong.
You should identify the quality of the piece. Ideally, the pieces should be well formed with a finely ground and finished pontil at the bottom.
Most of the fine opaline pieces were made by high end glass houses, so check for any quality clues that run afoul of the high quality standards and artistry of the finer producers.
Be sure to run your fingers around the entire piece to check for chips and flea bites. If you're buying online, check the condition report for any damage disclosures and look closely at the photographs or videos provided of the piece.
If the piece was painted or gilded, there may be some (or a lot of) loss to the decoration, depending on the age of the piece and how it was used. If the enamel or gilt loss isn't major and doesn't detract from the piece, it shouldn't be a turn-off. Chips or other damage, however will generally reduce the value of a piece by about 25%.
Pieces of fine antique French opaline run the gamut in price from a few hundred to tens of thousands of dollars.