Definition:

Kugels were the first Christmas decorations produced in Germany and authentic pieces are highly sought after by collectors.

John Lightner explained it in best when interviewed several years ago:

• The most popular shape for Kugels was balls, ranging in size of up to 30". They were also produced in different fruit molds, including berries and grapes.
• Kugels were made of very heavy glass.
• The color is in the glass, not painted on.

• Kugels had brass caps and rings
• According to the Golden Glow, a Christmas organization for antique enthusiasts, the most common colors are gold, yellow--green, cobalt, blue and pink-red. The rarest colors are the deep reds, burgundy, orange and amethyst, as the rarest of all.

Prices realized:

• Lot of ten Kugels, including one grape and Santa shaped Kugel, sold for $570.00 (Morphy's Auction September 2011)
• Two gold 4" Kugels, sold for $180.00 (Morphy's Auction September 2011)
• Set of six small kugels, 1 - 1.5" sold for $977.50 (Morphy's Auction September 2010
• Set of six larger kugels, sold for $316.50 (Morphy's Auction)
• Lot of six, includes one grape and one egg shaped Kugel, sold for $690.000 (Morphy's Auction September 2010)
• Set of 10 Kugels, ranging in size of up to 5", sold for $977.50 (Morphy's Auction September 2010)

Reproduction Note: They are being reproduced, I've seen numerous reproductions made in India and sold for just a few dollars at stores, but those same pieces can sometimes be found at antique shows and dealers, who may or may not know the difference.
Do your homework and buy from reputable sellers or auction houses.

It can be a little confusing for new collectors with so many different terms used to describe antique Christmas collectibles. Learn more unusual Christmas terms:
What's is a Dresden?
What does Free-Blown glass mean?
What is a Christmas Blow Mold?
What are Sebnitz ornaments?
Learn more about Antique German Glass Ornaments