Antique Glass Identification: Pattern Glass, Carnival Glass and How to Tell Them Apart

Narrow it down: the identification tool

Answer what you can see and skip the rest. The tool compares your answers with the clues in this guide and shows which kinds of glass fit best, with a plain label for how well. It cannot date a piece, name a maker or tell you a piece is old, because reproductions copy shapes, patterns and colors. Nothing you pick is sent anywhere.

How the tool decides: each answer adds or subtracts points for each kind of glass, using the clues cited in this guide. Labels run from “Strong match” to “Unlikely.” None of them means “certain.”

Eight kinds of glass at a glance

Dates are the ranges the cited sources give. Where sources differ, the sections below say so.

Blown, pressed or cut: how was it made?

Work out how a piece was formed before you hunt for a pattern name. Four checks do most of the work: the base, the seams, the inside surface and the edges.

1. Free-blown

   Blown on a pipe and held on a rod to finish. A bottle held by a pontil rod will almost always keep some evidence of it,^[1] and free-blown pieces have no mold seams.^[7]

2. Mold-blown

   Blown into a mold. Pattern-molded pieces show a soft pattern on both sides of the wall, and a full-size mold can leave seams where its parts met.^[2][7]

3. Pressed

   A plunger pushes hot glass into a multi-part mold. The outside takes the mold’s shape and the inside the plunger’s, so the two need not match. Seams are almost always visible.^[2]

4. Cut

   A wheel grinds the pattern in by hand. Any mold seams are removed by the cutting or polishing, and the detail is sharper than pressed glass.^[2][8]

Cut or pressed: five checks

Source for the table: Maryland Archaeological Conservation Laboratory.^[2] A pattern alone does not decide it, because pressed-glass makers copied cut-glass designs for decades.^[2][17]

Mold-blown or pressed?

Slide a fingertip over the inside. In pressed glass the inner shape comes from the plunger and need not match the outside. In pattern-molded glass the pattern shows on both sides, and in glass blown in a full-size mold a raised rib outside is a hollow inside.^[2] Pressed pieces were mostly open-mouthed, because the plunger had to come out. Tumblers, stemmed glasses and decanters were not pressed until the late 1830s.^[2] Machine blowing of stemware and tumblers began in 1897, and fully automatic production in the 1920s.^[2]

Pontil scars, and what a missing one proves

A pontil rod holds a piece while its rim or foot is finished. The scar it leaves depends on the rod: a sharp-edged ring from a hollow blowpipe, a patch of glass bumps and gouges from a solid bar, loose sand-like grains from a sand pontil, or red, gray or black residue from bare iron.^[1] Most scars turn up on American utilitarian bottles from the Civil War era or earlier. The term “open pontil” also names a large circular scar, about 5 inches across, on heavy dishware such as big bowls and platters.^[1]

No scar proves little. Fire polishing could remove most or all of the evidence, and makers ground the scar off some specialty bottles, notably decanters, on purpose.^[1] On pressed glass the pontil is usually polished smooth.^[2] For bottle bases, finishes and seams, use our bottle marks and dating guide.

Seams: count them, but don’t date by them

Pressed glass shows two, three or four seams depending on the shape: small pieces used two-piece molds, compotes three-piece molds, and large or square pieces four-piece molds. The Early American Pattern Glass Society says you will always find two, three or four seams running through pressed glass, though they are sometimes well hidden in the pattern, and that the number does not determine age.^[3] Bottle researchers go further and call the idea that a seam’s height dates a bottle one of the longest-running myths in bottle dating.^[7]

Decoration added after forming

Engraving scratches or stipples a design into the surface with diamond points or copper wheels, and leaves a frosted look; wheel engraving on English glass began around 1725.^[8] Acid etching covers the glass with a resist, scratches a design through it and dips the piece in hydrofluoric acid. The result is a matte or frosted design, and an English patent for the process was registered in 1857.^[18] Cutting uses rotating wheels and grit and favors straight-line motifs such as panels, flutes and fans.^[8]

Early American pattern glass (EAPG) and lacy glass

“EAPG” is collectors’ shorthand for American pressed tableware made from about 1850 to 1910, most of it in the 1880s. It was meant for everyday use and sold as full table settings or single pieces. Designs ran from plain to elaborate imitations of cut glass, with animal, fruit and floral motifs.^[3] Typical pieces were goblets, tumblers, compotes, creamers, spooners, covered sugars and celery vases.^[19]

Collectors know of more than 3,000 patterns.^[3] Patents covered designs and names, but competitors often made similar patterns and names once one sold well. A look-alike is therefore not proof of the same factory.^[3] Pressing with a hand-operated machine was first perfected in the United States in the early 1820s, and steam-powered presses in the 1890s improved quality while cutting costs.^[20]

Finding a pattern name

Describe the piece in five words: shape, motif, rim, base and what repeats. Then compare a photograph with a pattern reference instead of a written description. The Rakow Research Library’s pressed glass guide lists Early American Pattern Glass by Reilly and Jenks (2002), Pressed Glass in America by John and Elizabeth Welker (1986) and Identifying Pattern Glass Reproductions by Jenks, Luna and Reilly (1993).^[22] Marks are the other route; our glass makers’ marks guide covers the companies that marked their glass and when.

Depression glass, and how it differs from Elegant glass

The National Depression Glass Association describes Depression glass as mass-produced, machine-made “tank glass” from about 1920 to 1940, usually colored and of only fair quality.^[11] Another NDGA article dates it from the late 1920s to about 1940,^[4] and the Wolfsonian says it stayed popular through the 1930s and in production until the early 1950s.^[23] Many collectible patterns went on well past 1940, some into the 1960s.^[11] The sources are counting slightly different things, so treat the end date as a range.

American firms expanded their use of mechanical presses in the late 1920s to make cheap molded glassware.^[23] It was sold in nickel-and-dime stores and given away in boxes of food or soap, at movie “dish nights” and at gas stations.^[4][11][23] Kitchen and bath ware such as storage containers, mixing bowls and juicers were common product types.^[11] Colors include pink, green, yellow, amber, pale blue, clear, ruby red and deep cobalt blue.^[4]

Sources: Cotter and Nagy, National Depression Glass Association.^[4][11] Straw marks, bubbles, slightly irregular shapes and color that varies from batch to batch, even within a day, are normal in Depression glass. Obvious cracks and chips are not.^[4][11]

Carnival glass and its iridescent cousins

Carnival glass is pressed glass with a metallic, color-shifting surface. It was pressed in patterned molds and sprayed with metallic salts while very hot.^[5] The Carnival Glass Society (UK) adds that the piece was reheated, sprayed with a solution of metallic salts and then annealed, and that the final look depended on the chemistry of the salts, the glass temperature and how many times the process was repeated.^[9]

The glass was very popular in the United States from about 1908 to 1915 and was exported to several countries. By the 1950s collectors were eagerly seeking it, and the name “carnival glass” was coined from stories that some pieces had been prizes at midway games. Kent State presents that as a story, not a confirmed fact.^[5]

Kent State names these five as the major makers; a few other firms made smaller amounts.^[5] The Carnival Glass Society also lists Westmoreland and United Glass, and says European makers worked in much smaller volumes.^[9] Dates differ by a year or so between sources, so we give the ranges they give.

Four checks for carnival

• Look through the base with a strong light behind it. The base glass shows the underlying color (purple, green, blue). Marigold is the exception, because its base glass is generally clear.^[9]
• Name the finish. Satin is matte, electric is vibrant and many-colored, and radium is glossy and often found on Millersburg pieces.^[9]
• Look at the shape. Ruffled, crimped, piecrust and “jack in the pulpit” edges are typical, and so are swung vases with stretched patterns.^[9]
• Find the molded pattern. It may be on the outside or the inside of the piece.^[9]

Iridescent, but not carnival

Stretch glass is iridescent with little or no pattern, usually just ribs, panels, rings or an optic. It was pressed or blown into a mold, never free-blown, so it has no pontil mark. After spraying, workers shaped it with paddles and crimpers, and that hand-working stretched the iridescent surface into “cobweb,” “crackle” or “onion skin” marks.^[10] The NDGA article dates it from about 1916 to the early 1930s; the Stretch Glass Society gives about 1912 to 1932.^[10][14]

Water-ambered glass, often EAPG-based, is not carnival glass even when it has a light iridescence.^[26] Hand-blown iridescent art glass, such as Tiffany’s, is what carnival imitated, and it is outside this guide.^[27]

Color, glow and black lights

Color in glass usually comes from metallic oxides such as iron, manganese, copper, cobalt, tin, nickel, silver and chromium.^[15] A UV lamp can reveal a few of those ingredients, but only chemical analysis settles a composition. Fluorescence reflects refining agents, furnace atmosphere and melting temperature as much as the type of glass, so the Maryland laboratory says to use it carefully.^[6]

What a black light can show

Uranium glass: Vaseline, canary and custard

Uranium was first used to color glass in the 1830s. “Vaseline glass” means transparent yellow to yellow-green glass colored by uranium, and “canary glass” is an older name from the 1840s.^[16] Uranium glass also came in opaque and opalescent green, white and pink, and regular production in the United States continued until just before World War II.^[15] It paused for about fifteen years from the war and resumed in 1959 with depleted uranium. Uranium content is often about 2 percent by weight, and some glass made in the early 1900s reached 25 percent.^[16]

Custard glass is an opaque yellow glass made from the 1870s with uranium and sulphur in the mix, so most U.S. custard glass glows under UV. It was very popular in the United States from about 1895 to around 1908.^[13] Some yellow glass is colored with other additives, such as cerium oxide, and can look identical by daylight, which is why the UV test helps.^[16]

A glow does not date a piece, because new uranium glass exists. The EPA says U.S. glassmakers and ceramic producers stopped using radionuclides for color after 1970 and that a few other countries still use them; ORAU says a few U.S. companies were still making Vaseline glass in 2004. The sources disagree on modern U.S. production, and either way a glow shows what is in the glass, not when it was made.^[16][28]

Sun-colored purple glass

Some colorless-looking glass turned lavender after years in the sun. Glassmakers added manganese dioxide to cancel the green tint that iron in the sand causes, and ultraviolet light starts an electron exchange between the manganese and iron ions that produces the purple.^[12][30] The Rakow Library says the change is sometimes reversible by gently heating the glass to about 200 °C; we would not try that on anything you want to keep.^[30] The color builds under strong sunlight over a number of years.^[31] Because the tint depends on the manganese in the batch and the sun the piece has seen, it is a hint about the recipe, not a date. Most manganese-decolorized glass found on archaeological sites was made between about 1880 and the 1920s.^[12]

Opalescent glass

A milky-white edge or raised pattern on a colored pressed piece is opalescent glass. The effect comes from reheating parts of the vessel so they turn white, and many U.S. factories made it between 1880 and 1920.^[15]

Reproductions, reissues and fakes: warning signs

Reissue

A new piece made by the original maker, often from the old mold.^[26]

Reproduction

A piece made from old or re-made molds by a different factory.^[26]

Fake

A piece made on purpose to be passed off as genuine.^[26]

• The right mold proves little.

  After Heisey closed in 1957, Imperial and later the Heisey Collectors made new pieces from the original Heisey molds.^[37] Imperial’s early-1960s “New Carnival” line used molds from ware that had been popular about fifty years earlier.^[25] Mosser made a Dahlia pitcher from the old Dugan-Diamond mold, and Summit made pieces from Westmoreland molds.^[26]

• Marks cut both ways.

  Fenton reissues are usually marked with its logo, but reproductions carry the new maker’s mark only sometimes, and some contemporary pieces were made without removing the original maker’s mark.^[26] Watch for a dull or buffed spot where a logo may have been ground off, and remember that some sellers remove or alter marks on purpose.^[38]

• A color the pattern never came in.

  For Depression glass, be wary of glassware in a color never produced in that pattern, a pattern that is faint and lacks the detail of the original, or a “greasy” feel.^[4]

• Shortcuts disagree.

  One reproduction list says new carnival may show a brighter, brassier iridescence and feel heavy, with exceptions.^[38] Carnival Glass Worldwide calls the idea that new carnival is shinier and old carnival satin “very misleading,” and points to glossy Millersburg radium and many Imperial pieces as shiny originals.^[26] Treat every shortcut as a hint.

• Foreign copies and borrowed molds.

  Many Depression glass patterns have been reproduced, often by foreign makers; Chinese makers produced many Cherry Blossom and Jadeite pieces, and Indiana Glass bought molds from other companies and reproduced some patterns.^[11] Carnival Glass Worldwide lists fake Good Luck, Peacock and Grape and Cable bowls made in the Far East.^[26]

• A glow is not an age.

  New uranium glass exists, and a weak yellowish-green glow is a common response from many non-lead glasses of different periods.^[16][28][29]

No single test settles it. The Rakow Library’s list includes a whole book on the subject, Identifying Pattern Glass Reproductions (1993).^[22] Carnival Glass Worldwide recommends three habits: assume nothing, check everything and follow the evidence.^[26]

Step by step: the identification flow

The tool above runs these steps for you. Here they are on paper.

1. Record it before you clean it

   Photograph every side and the base with a ruler in the frame, and note height, weight and any mark. Our research method has the full routine.

2. Turn it over

   A rough scar suggests hand-blowing. A smooth spot or no scar tells you much less, because pontils were ground and polished away.^[1][2]

3. Trace the seams

   None suggests free-blown or cut glass. Clear seams up the sides and across the rim suggest pressing.^[2]

4. Feel the inside

   Pattern on both sides of the wall suggests mold-blowing. A smooth or differently shaped inside suggests pressing.^[2]

5. Run a fingertip over the edges

   Sharp, crisp edges and fine striations suggest cutting. Rounded, identical repeats suggest pressing.^[2]

6. Read the pattern and shape

   A dotted, lace-like background suggests lacy glass. Matching sets of goblets and compotes suggest pattern glass. Pink or green kitchen ware suggests Depression glass.^{[2][4][11][19]}

7. Tilt it in the light

   A metallic rainbow sheen over a molded pattern suggests carnival glass; the same sheen with little pattern suggests stretch glass.^[5][10]

8. Optional: use a black light, safely

   Read the result as a clue to the recipe of the glass, not a date.^[6] Follow the safety notes above.

9. Compare, ask, and say “consistent with”

   Match against reference photos, then ask a society. Until you have, write “consistent with” rather than “is.”

Printable field checklist and record sheet

Two US Letter PDFs for the show table, the estate sale or the classroom. Both are free to print and share under CC BY 4.0.

• Antique Glass Field ChecklistTwo pages. Page one is nine checks with what each result suggests; page two covers reproduction warning signs, black-light safety and who to ask.PDF, US Letter, 2 pages, 104 KB
• Glass Record SheetOne page to describe a piece for a pattern search or a club: size, base, seams, edges, color, UV result, photos taken and pattern references tried.PDF, US Letter, 1 page, 42 KB

Where to take a question next

Collector societies and museum libraries are where pattern and reproduction knowledge lives. Every address below answered when we checked on November 3, 2026. For a longer list of clubs and museums, see the directory in our glass marks guide. We do not value pieces; for that, see how to choose a qualified appraiser.

• Early American Pattern Glass SocietyArticles on pressed glass history, forms and uses in its Shared Glass Knowledge section.^[3][19]eapgs.org
• National Depression Glass AssociationAn article library covering Depression, Elegant, carnival and stretch glass.^[10][11]ndga.net
• The Carnival Glass Society (UK)A concise guide to carnival glass, in sections.^[9]thecgs.co.uk
• Carnival Glass WorldwideA reference site with pages on reissues, reproductions and fakes, and on colors such as purple and amethyst.^[26][31]carnivalglassworldwide.com
• Stretch Glass SocietyA society for iridescent stretch glass.^[14]stretchglasssociety.org
• Heisey Glass MuseumA museum with an exhibit on reissues and look-alikes of Heisey glass.^[37]heiseymuseum.org
• Imperial Glass historyThe Imperial Glass Company’s history, trademarks and reissues.^[25]imperialglass.org
• Rakow Research Library, Corning Museum of GlassA pressed glass research guide with books and links. The library takes questions and visits by appointment, but cannot answer questions about rarity or value.^[22][39]libguides.cmog.org
• The Henry Ford, Digital CollectionsDated museum pieces to compare, in its pressed glass expert set.^[21]thehenryford.org

For teachers, librarians and site owners

How we built this page

We opened every source listed below on November 3, 2026 and wrote each claim from what the source says. Where sources disagree, the page says so instead of picking one. The tool’s weights are our editorial reading of those clues, not a trained model, and the tool says “consistent with” because that is all a checklist can honestly say.

Three sources we tried would not open for automated reading: the Corning Museum of Glass dictionary, Encyclopædia Britannica and the American Cut Glass Association website. We did not cite them. For Corning we used the Rakow Research Library’s guides and its answered questions instead. The Rakow Library says it cannot answer questions about the rarity or value of your glass.^[39] The artwork is drawn in code; there are no AI images and no photographs of real glass on this page.

More from The Mark Index:

• Glass Makers’ MarksHeisey, Fenton, Imperial, Anchor Hocking and more, with sourced dates.
• Bottle Marks and Bottle DatingBases, seams, finishes and manufacturer marks on glass bottles.
• How to Research an AntiqueA step-by-step method, plus appraisers, clubs and libraries.
• Mark Reference DirectoryLink-checked books, databases and societies for marks.

Sources

1. ResearchLindsey, Bill. "Pontil Scars." Historic Glass Bottle Identification & Information Website, Society for Historical Archaeology / Bureau of Land Management, accessed 2026-11-03. secure-sha.org
2. ResearchSamford, Patricia. "Hot Glass Decoration." Table Glass, Diagnostic Artifacts, Maryland Archaeological Conservation Laboratory, accessed 2026-11-03. apps.jefpat.maryland.gov
3. SocietyGeorge, Sean, and Wendy Jones. "A Brief History of Antique Pressed Glass." Early American Pattern Glass Society (EAPGS) website, Shared Glass Knowledge, accessed 2026-11-03. eapgs.org
4. SocietyNagy, Christine. "A Depression Glass Primer." National Depression Glass Association, last updated January 13, 2009, accessed 2026-11-03. ndga.net
5. MuseumKent State University Museum. "Carnival Glass: The First Decade" (exhibition, 2006-2008; guest curator Jim Measell), accessed 2026-11-03. kent.edu
6. ResearchSamford, Patricia. "Glass Composition." Table Glass, Diagnostic Artifacts, Maryland Archaeological Conservation Laboratory, accessed 2026-11-03. apps.jefpat.maryland.gov
7. ResearchLindsey, Bill. "Body & Mold Seams." Historic Glass Bottle Identification & Information Website, Society for Historical Archaeology / Bureau of Land Management, accessed 2026-11-03. secure-sha.org
8. ResearchSamford, Patricia. "Abrasive Decoration." Table Glass, Diagnostic Artifacts, Maryland Archaeological Conservation Laboratory, accessed 2026-11-03. apps.jefpat.maryland.gov
9. SocietyCarnival Glass Society (UK). "Carnival Glass: A Concise Guide," section 2, thecgs.co.uk, accessed 2026-11-03. thecgs.co.uk
10. SocietyJones, Helen, and Roberts Jones. "Stretch, that 'Other' Iridescent Glass." National Depression Glass Association, last updated April 23, 2009, accessed 2026-11-03. ndga.net
11. SocietyCotter, Tom. "What is Depression Glass? For That Matter, What is Elegant Glass?" National Depression Glass Association, last updated May 9, 2015, accessed 2026-11-03. ndga.net
12. ResearchSamford, Patricia. "Colorless Glass." Table Glass, Diagnostic Artifacts, Maryland Archaeological Conservation Laboratory, accessed 2026-11-03. apps.jefpat.maryland.gov
13. ReferenceBowey, Angela M. "Custard Glass." Glass Encyclopedia, glassencyclopedia.com, accessed 2026-11-03. glassencyclopedia.com
14. SocietyStretch Glass Society. Home page (mission statement), stretchglasssociety.org, accessed 2026-11-03. stretchglasssociety.org
15. ResearchSamford, Patricia. "Colored Glass." Table Glass, Diagnostic Artifacts, Maryland Archaeological Conservation Laboratory, accessed 2026-11-03. apps.jefpat.maryland.gov
16. MuseumOak Ridge Associated Universities, Museum of Radiation and Radioactivity. "Vaseline Glass (Uranium Glass)," Health Physics Historical Instrumentation Museum Collection, accessed 2026-11-03. orau.org
17. MuseumSable, Charles. "Curator's Choice: Irish Glass." The Henry Ford blog, February 28, 2014, accessed 2026-11-03. thehenryford.org
18. ResearchSamford, Patricia. "Chemical Decoration." Table Glass, Diagnostic Artifacts, Maryland Archaeological Conservation Laboratory, accessed 2026-11-03. apps.jefpat.maryland.gov
19. SocietyGeorge, Sean, and Wendy Jones. "Original and Modern Uses of Antique Pressed Glass." Early American Pattern Glass Society website, Shared Glass Knowledge, accessed 2026-11-03. eapgs.org
20. MuseumVictoria and Albert Museum. Celery-jar, press-moulded glass, O'Hara Glass Co., Pittsburgh, about 1890 (C.28-2012), object record, accessed 2026-11-03. collections.vam.ac.uk
21. MuseumThe Henry Ford. "Pressed Glass" (expert set), Digital Collections, Dearborn, Michigan, accessed 2026-11-03. thehenryford.org
22. MuseumRakow Research Library, The Corning Museum of Glass. "Pressed Glass," American Glass research guide, last updated October 5, 2026, accessed 2026-11-03. libguides.cmog.org
23. MuseumThe Wolfsonian-FIU. "Color and Form: American Depression Glass" (exhibition, December 3, 2020 to September 5, 2021), accessed 2026-11-03. wolfsonian.org
24. SocietyDoty, David. "A Brief History of Carnival Glass." National Depression Glass Association (NDGA), last updated January 9, 2008, accessed 2026-11-03. ndga.net
25. SocietyImperial Glass Company / National Imperial Glass Collectors' Society. "History," imperialglass.org, accessed 2026-11-03. imperialglass.org
26. ReferenceThistlewood, Glen, and Stephen Thistlewood. "Reissues, Reproductions and Fakes." Carnival Glass Worldwide, accessed 2026-11-03. carnivalglassworldwide.com
27. ReferenceSix, Dean. "Fenton Art Glass Company." e-WV: The West Virginia Encyclopedia, revised February 20, 2024, accessed 2026-11-03. wvencyclopedia.org
28. GovernmentU.S. Environmental Protection Agency. "Radioactivity in Antiques," RadTown (archived snapshot of January 19, 2025; page last updated December 3, 2024), accessed 2026-11-03. 19january2025snapshot.epa.gov
29. MuseumRakow Research Library, The Corning Museum of Glass. "Why would clear glass show a greenish glow under black light?" Ask a Glass Question FAQ 144060 (answer by Robert Brill; page updated November 23, 2021), accessed 2026-11-03. libanswers.cmog.org
30. MuseumRakow Research Library, The Corning Museum of Glass. "What causes the varied purple hues in old glass bottles?" Ask a Glass Question FAQ 144135, updated February 17, 2025, accessed 2026-11-03. libanswers.cmog.org
31. ReferenceThistlewood, Glen, and Stephen Thistlewood. "Purple and Amethyst." Carnival Glass Worldwide, accessed 2026-11-03. carnivalglassworldwide.com
32. GovernmentU.S. Food and Drug Administration. "Ultraviolet (UV) Radiation" (content current as of 08/19/2020), accessed 2026-11-03. fda.gov
33. GovernmentWorld Health Organization. "Ultraviolet radiation" fact sheet, June 21, 2022, accessed 2026-11-03. who.int
34. SocietyJohnson, Ray, CHP. Answer to question #11320, "Ask the Experts," Health Physics Society, posted September 18, 2015, accessed 2026-11-03. hps.org
35. ResearchWatson, S. J., and J. S. Hughes. "Radiological implications of the use of uranium in vaseline glass." Journal of Radiological Protection 30(3): 535-544, 2010. doi:10.1088/0952-4746/30/3/008 (UKHSA research portal record), accessed 2026-11-03. researchportal.ukhsa.gov.uk
36. MuseumDavis, Amber. "A 'glowing' review of uranium glass." ORAU Then & Now blog, January 22, 2025, accessed 2026-11-03. orau.org
37. MuseumHeisey Collectors of America / National Heisey Glass Museum. "Exhibits" (Reproductions and Look-Alikes), heiseymuseum.org, accessed 2026-11-03. heiseymuseum.org
38. ReferenceBlair, Elaine. "Carnival Glass: Reproductions-at-a-Glance." Hooked on Carnival, accessed 2026-11-03. hookedoncarnival.com
39. MuseumRakow Research Library, The Corning Museum of Glass. "Could it be said that Fire-King is Pyrex before Pyrex?" Ask a Glass Question FAQ 143773 (used for what the library will and will not answer), updated July 17, 2025, accessed 2026-11-03. libanswers.cmog.org

General information to help you identify glass. It is not an appraisal, an authentication or a safety certification. Radiation and ultraviolet notes summarize the cited agency, museum and laboratory sources; follow your own regulator’s advice. We never put values on anything.