Above: Real sea glass left, fake sea glass right.

Genuine sea or beach glass comes from discarded bottles, tableware, or household items and is found in oceans, lakes, and rivers. Genuine sea or beach glass tends to have:

• Lettering, embossed images, and distinguishing features such as handles, bottle necks, etc.
• A frosted patina on the surface with small “C”-shaped patterns, surface cracking, rounded edges, and small crevices where grains of sand may be found.

Above: Real sea glass pieces on left in each photo, tumbled sea glass right.

Artificial glass comes from broken glass that has been machine tumbled, sand blasted, or immersed in acid-etching chemicals. Artificial glass tends to have:

• A uniform texture and nearly uniform square, oval, or triangle shapes.
• A satiny smooth surface, without “C”-shaped marks, embossed shapes, or other distinguishing features.
• Unusual or rare colors.
• Sharp or angular edges or chunky shapes.

Above: Artificial sea glass made from vase fillers.

Above: Fake sea glass made with a rock tumbler.

Sea Glass Buying Tips

It pays to be an educated consumer when purchasing sea or beach glass. 

• Purchase loose glass, jewelry, and products from a International Sea Glass Association member. All members pledge to use only genuine, unaltered sea or beach glass. 
• Just because the seller is advertising that they have sea or beach glass does not mean that it has ever been on a beach.
• If you can’t see the condition of the glass in a photo, ask for additional photos before buying online.
• Sellers price differently, so a high price doesn’t indicate authenticity. However, rare-colored glass at a very low price is probably not genuine sea or beach glass.
• These are general tips. Genuine sea and beach glass from certain locations can be naturally smooth, and some manufacturing techniques create faux “C”-shaped marks that mimic real sea or beach glass. Buy directly from beachcombers and ISGA members so you know the glass is real.

Read more about Genuine, Artificial and Altered Sea Glass.

The International Sea Glass Association (ISGA) was formed to educate the public about authentic sea and beach glass. Professional members are carefully screened prior to membership and agree to work only with and sell products made with real sea or beach glass. ISGA is an excellent resource for sea and beach glass enthusiasts. See the current list of members.

In this photo, genuine beach found sea glass on the left and artificially tumbled craft glass on the right.

The same photo as above, with the artificially tumbled craft glass covered up.

Another photo of artificial tumbled “sea glass”.