How do you know if old glass is valuable?

Tips for Identifying Antique Glass Using Marks and Other Clues. Most pieces of old glass do not have any glass markings. Check for excessive wear and scratches on the bottom. If the piece is gilded, it may show signs of wear.

How do you find the value of vintage?

Where to Find Antique ValuesCollect.com. Collect.com allows you to buy and sell antiques and collectibles. David Doty. David Doty has a vast amount of information on his site about Carnival glass. Coin Guide. Coin Guide has a large data base of antique and collectible coins and their values. Antiques Navigator.

What is the rarest color carnival glass?

According to Colleywood Carnival Glass, the following colors are among the rarest and most valuable:Fenton Ambergina - a deep orange-red tone.Northwood Marigold - a warm-toned deep yellow.Fenton Cherry Red - a dark, glowing red.Northwood Black Amethyst - a very dark purple that appears almost black.More items

What is vintage blue glass called?

Cobalt glass—known as smalt when ground as a pigment—is a deep blue coloured glass prepared by including a cobalt compound, typically cobalt oxide or cobalt carbonate, in a glass melt. Cobalt is a very intense colouring agent and very little is required to show a noticeable amount of colour.