Q. These two Delft plaques were acquired in Europe by my great-aunt and then passed down in the family. They are each 21 inches tall and are marked "De la Maison Joost Thooft et Labouchere" as well as "Delft" and "Holland." They have a few glaze chips and one has a crack that is original to when the piece was made. We would like to know their monetary value.

A. Delft is both a city in Holland and a type of earthenware covered with a thick glaze that has been whitened with tin oxide.

The Dutch had been introduced to Chinese porcelain in the 16th and 17th centuries, and they wanted to imitate these highly desirable wares. Unfortunately, Dutch potters had no idea how to make porcelain, so they decided to use a brilliant white glaze on an earthenware body as the perfect backdrop for painted decoration.

This substitution was less expensive, and it was (and still is) popular with the consuming public. When this sort of ware is manufactured in Holland, it is called "Delft," but when a similar ware is made in England, it is called "delft," with a lower-case "d."

In 1653, a factory known as "De Porceleyne Fles" ("The Porcelain Bottle" or "The Porcelain Jar," depending on the translation you favor) was established in Delft, but it ran into trouble in the 19th century. It was acquired in 1874 (some sources say 1876) by Joost Thooft, a local engineer who wanted to improve the product.

Thooft's business partner was Abel Labouchere, and together they tried to develop a superior blue pigment and a stronger white earthenware body to be used in the manufacture. Interestingly, this firm still exists and a Labouchere is still in the company's management.

The two plaques in today's question were probably made between 1891 and 1919, and are on rococo-style palette-shaped mounts that are really quite lovely. At 21 inches, the pieces in today's question are a very good size. The example with the windmill is typical and should be valued for insurance purposes in the $450-to-$600 range if the condition is good with no unsightly chips.

The other piece is by far the more attractive, with skaters on a pond, but if the long scar in the upper left quadrant is original (i.e., in the making) as you maintain, the piece is unquestionably a "second" (an item that a company sold even though it was in less-than-perfect condition). This piece should be valued for about half the other piece or a bit less.

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