"I look across a room and if I see a shape that's the wrong shape for what it's purported to be, I'll get closer and look at the design, and then flip it over and look at the clay.
I'll put all those things together to place it to a particular culture, manufacturer, and a time in history.
In the late 17th and early 18th centuries, spherical teapots were very popular in the West.
If you find a spherical teapot that a seller claims has been made in, say, the late 16th century, be suspicious.
"In the late 19th century in Holland, it was very popular to have large, under-glazed blue scenic decorated dishes," Lark explains, noting that these dishes could run 25 inches wide.
"This size dish was popular in this period, and when you see one there's a good chance it's from Holland, or maybe Japan, at the same time." The shape of a piece can also peg it to a particular time in history.
We've all seen white and blue porcelain before—maybe while strolling around a Chinatown chatchka shop, a first-rate art museum, in Macy's decorative wares department, or even at a neighborhood yard sale.
The blue on this glaze indicates it was made in Japan.
"If a chip shows a grainy surface that is not fused together then it probably is not porcelain and did not come from Asia," Lark says.
Most other kinds of ceramics are opaque—even glassy-looking varieties such as fritware, which has a sand-based ceramic body, and Delft, made with tin to give it the appearance of porcelain.
If you look at the base of a piece, or at the clay interior that might be revealed by a chip, you can also get a sense of whether an object really is porcelain.
From that, I'm able to come up with whether an item is what it's supposed to be and how much it's worth." Here's how you can learn to do the same.
Shape It Up Lark says that one of the easiest ways to begin evaluating blue-and-white porcelain is to evaluate an object's shape, which pins a piece to a particular place.