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.

A natural nuclear reactor is therefore no longer possible on Earth without heavy water or graphite. The Oklo uranium ore deposits are the only known sites in which natural nuclear reactors existed. Studies have suggested this as a useful natural analogue for nuclear waste disposal.

Pure uranium is a silvery metal that quickly oxidizes in air. Uranium is sometimes used to color glass, which glows greenish-yellow under black light — but not because of radioactivity (the glass is only the tiniest bit radioactive).

Fenton Marks: The Fenton in an oval logo was first used on Carnival Glass in 1970. The next line to be marked was Hobnail in 1972-1973. By 1975 the logo had been added to all Fenton items. Fenton added a small number 8 to the logo used for the 80’s decade, 9 for 90’s decade and 0 for 2000 to the present.

Pink glass

Milk Glass Is Opaque Like milk, this type of glass is mostly opaque. If you hold a piece of pink Depression glass up to the light, you can see right through it. In contrast, the opaque milk glass blocks most of the light.

Most early milk glass is not marked. Various companies began marking their glass in the 1950s, 1960s or 1970s.

krisanapong detraphiphat / Getty Images. American milk glass is a popular collector’s item that primarily dates back to the turn of the 19th century up through the 1950s. It is also called clambroth glass, resembling the color of the milky, translucent cooking liquid.

Naturally, a lot of glassware doesn’t have the same provenance as China and other porcelain products when it comes to age, but some of it is still pretty extraordinary. The most expensive piece of glassware ever sold at auction was a Roman glass bowl, intact after 1,700 years of existence.

5 World’s Most Valuable Antiques and Collectibles of All Time

1. Pinner Qing Dynasty Vase – $80.2 million. Source.
2. Ru Guanyao Brush Washer Bowl – $37.68 million. Source.
3. Record-Breaking Persian Rug – $33.76 million. Source.
4. Leonardo da Vinci’s Codex Leicester – $30.8 million. Source.
5. Patek Philippe Supercomplication Pocket Watch – $24 million. Source.

Tapping genuine crystal emits a musical “ping” sound. Well-known crystal manufacturers typically marked the bottom of their wares with a signature or company name, which can help determine their value. Another factor is appearance: the more intricate a piece’s cuts and stems, the more value it holds.

Crystal Stemware Manufacturer Marks

1. You could find the mark on the rim or center of the foot, on the stem, or on the bottom of the bowl.
2. The mark could be an initial, a logo, a word, or coded numbers and letters.
3. Some marks are molded or embossed, others are stamped or etched on the glass (Waterford, for example).

The first way to tell an authentic piece of Waterford is to look for the Waterford acid mark. Using a magnifying glass, or holding the crystal up to the light, search for the stamp. It will most likely appear on the stem’s base, but can also be found in the grooves as well.

Visually inspect the individual pieces of crystal, if there is a mark or logo etched in them then they are most likely real, quality crystal. Do the individual pieces sparkle and show colour and “fire”? If the pieces look like ordinary glass then they may well be that or a low quality crystal.