Unmasking the Mystery: A Comprehensive Guide to Identifying Vaseline Glass
Vaseline glass, also known as uranium glass, is a captivating and collectible type of glassware characterized by its distinctive yellow-green hue and its ability to glow under ultraviolet (UV) light. This fascinating property is due to the presence of uranium oxide added to the glass mixture during production. While the amount of uranium used is typically small (usually less than 2%), it’s enough to create a noticeable fluorescence that makes Vaseline glass highly sought after by collectors. Identifying genuine Vaseline glass requires a combination of observation, knowledge, and sometimes, a little bit of technology. This comprehensive guide will walk you through the various methods and characteristics that can help you determine whether a piece is truly Vaseline glass.
## What is Vaseline Glass?
Before diving into identification techniques, it’s important to understand what exactly constitutes Vaseline glass. The term “Vaseline glass” originated from its color, which resembles the color of Vaseline petroleum jelly manufactured in the late 19th and early 20th centuries. While yellow-green is the most common color, Vaseline glass can also be found in other shades, including yellow, green, and even slightly blue-green. The key identifier, however, remains its reaction to UV light.
While all Vaseline glass contains uranium, not all uranium glass is Vaseline glass. Other uranium glass colors such as custard glass, jadeite and Burmese exist and are named accordingly. Vaseline glass specifically refers to transparent or translucent glass with a yellowish-green hue. Opaque varieties, while containing uranium, aren’t typically referred to as Vaseline glass.
## Why Identify Vaseline Glass?
Identifying Vaseline glass accurately is crucial for several reasons:
* **Authenticity and Value:** Genuine Vaseline glass pieces, especially those from certain manufacturers or time periods, can be quite valuable. Correct identification ensures you’re accurately assessing the worth of a piece you own or are considering purchasing.
* **Collection Building:** For serious collectors, knowing how to distinguish Vaseline glass from similar-looking glassware is essential for building a well-curated collection.
* **Historical Significance:** Vaseline glass production peaked in the late 19th and early 20th centuries. Identifying a piece connects you to a rich history of glassmaking and design.
* **Avoiding Misrepresentation:** Sadly, not all sellers are honest. Knowing how to identify Vaseline glass helps you avoid being misled by mislabeled or falsely advertised items.
* **Safety Awareness:** Although the level of radiation emitted by Vaseline glass is generally considered low and safe, understanding that it contains uranium allows you to handle it responsibly.
## The Identification Process: A Step-by-Step Guide
Here’s a detailed breakdown of how to identify Vaseline glass:
**Step 1: Visual Inspection – The Color Test**
* **Examine the Color in Natural Light:** The first step is to carefully examine the color of the glass in natural light. Vaseline glass typically exhibits a distinctive yellow-green hue. This color can range from a pale, almost lemon yellow, to a more vibrant, grassy green. Avoid making judgments solely under artificial light, as it can distort the true color.
* **Look for Transparency:** Vaseline glass is typically transparent or translucent. While variations exist, a high degree of opacity might indicate that it is not true Vaseline glass, but another form of uranium glass like Jadeite.
* **Beware of Imitations:** Be aware that some modern glassmakers attempt to replicate the color of Vaseline glass using other colorants. These imitations will *not* glow under UV light.
**Step 2: The UV Light Test – The Tell-Tale Glow**
This is the most reliable method for identifying Vaseline glass.
* **Acquire a UV Light:** You’ll need a UV light source, also known as a black light. Two main types are used: shortwave (254nm) and longwave (365nm). Shortwave UV lights produce a more intense glow but can be more harmful to the eyes and skin, so use them with caution and protective eyewear. Longwave UV lights are generally safer and more readily available, but the glow may be slightly less intense.
* **Darken the Room:** Turn off the lights in the room or find a dark space to conduct the test. This will make the fluorescence more visible.
* **Shine the UV Light:** Shine the UV light on the glass piece. Authentic Vaseline glass will glow with a bright green fluorescence. The intensity of the glow can vary depending on the uranium content and the type of UV light used. A strong, vibrant glow is a good indicator of genuine Vaseline glass.
* **Observe the Reaction:** Pay close attention to the color and intensity of the glow. A faint or absent glow suggests that the piece is likely not Vaseline glass. Some other types of glass might exhibit a slight fluorescence, but it won’t be the characteristic bright green of uranium.
* **Compare with Known Samples:** If possible, compare the glow of the suspected Vaseline glass piece with that of a known authentic sample. This can help you calibrate your eye and better distinguish genuine fluorescence.
**Step 3: Examining for Manufacturing Marks and Characteristics**
While not foolproof, examining the piece for manufacturing marks and characteristics can provide clues about its origin and potential authenticity.
* **Look for Maker’s Marks:** Many glass manufacturers used distinctive marks on their products. Research common marks used by companies known for producing Vaseline glass, such as Fenton, Cambridge, and Fry. Note that the absence of a mark does not automatically mean the piece is not Vaseline glass, as many older pieces were unmarked.
* **Consider the Era:** Vaseline glass was most popular from the late 19th century through the mid-20th century. The style, design, and manufacturing techniques used during these periods can provide clues about the piece’s age and potential authenticity. Research the typical patterns and styles associated with Vaseline glass from different eras.
* **Check for Mold Marks and Seams:** Examine the piece for mold marks or seams. The presence and type of these marks can indicate the manufacturing process used and potentially help determine the age of the piece. Hand-blown glass, for example, will not have seams.
* **Look for Imperfections:** Older glass pieces often have minor imperfections, such as bubbles or slight variations in color. These imperfections can be a sign of handmade or early machine-made glass and can add to the piece’s character and value.
**Step 4: Assessing the Weight and Density**
Vaseline glass tends to be heavier than comparable pieces of ordinary glass due to the presence of uranium. While this isn’t a definitive test, it can be a helpful indicator.
* **Compare with Similar Items:** Compare the weight of the suspected Vaseline glass piece with that of a similar item made of ordinary glass. If the Vaseline glass piece feels noticeably heavier, it could be a good sign.
* **Consider the Size:** Be sure to consider the size and shape of the items being compared. A larger piece of ordinary glass will naturally weigh more than a smaller piece of Vaseline glass. The comparison should be made between items of similar size and form.
* **Use a Scale (Optional):** If you have access to a sensitive scale, you can weigh the piece and compare its density to that of known Vaseline glass. However, this is not always practical and requires a reference point.
**Step 5: The Tap Test (Use with Caution)**
This test involves gently tapping the glass and listening to the sound it produces. Vaseline glass often has a distinct ringing tone compared to ordinary glass.
* **Tap Gently:** Tap the glass gently with your fingernail or a soft object. Avoid tapping too hard, as you could damage the piece.
* **Listen to the Tone:** Listen carefully to the sound produced. Vaseline glass often has a clearer, more resonant ringing tone compared to the duller thud of ordinary glass.
* **Practice Makes Perfect:** This test takes practice to master. Listen to the sound of known Vaseline glass pieces to develop your ear for the characteristic tone. It is also subjective and can vary based on the shape and thickness of the glass.
**Step 6: Research and Consult with Experts**
* **Online Resources:** Utilize online resources such as antique glass websites, collector forums, and online databases to research the characteristics of Vaseline glass. Many websites feature photographs, descriptions, and information about different manufacturers and patterns.
* **Books and Guides:** Consult books and guides dedicated to antique glass and Vaseline glass. These resources often provide detailed information about the history, manufacturing techniques, and identifying features of Vaseline glass.
* **Antique Dealers and Appraisers:** Consult with experienced antique dealers or appraisers specializing in glass. They can provide expert opinions on the authenticity and value of a piece.
* **Collector Groups:** Join local or online collector groups. These groups can provide valuable insights, advice, and opportunities to learn from experienced collectors.
## Common Mistakes to Avoid
* **Relying Solely on Color:** Don’t rely solely on the color to identify Vaseline glass. As mentioned earlier, some modern glassmakers imitate the color using other colorants.
* **Ignoring the UV Light Test:** The UV light test is the most reliable method for identifying Vaseline glass. Don’t skip this step.
* **Confusing with Other Types of Glass:** Be aware of other types of glass that may resemble Vaseline glass, such as Depression glass or carnival glass. While these types of glass may be collectible, they are not the same as Vaseline glass.
* **Overlooking Imperfections:** Don’t dismiss a piece simply because it has minor imperfections. Older glass pieces often have imperfections that add to their character and value.
* **Assuming All Glowing Glass is Vaseline Glass:** While a green glow under UV is a strong indicator, some modern glass may contain substances that fluoresce. Always consider the other characteristics mentioned above.
## Is Vaseline Glass Radioactive? A Note on Safety
Vaseline glass contains uranium, which is a radioactive element. However, the amount of uranium in Vaseline glass is typically small, and the level of radiation emitted is generally considered low and safe. The radiation emitted is primarily alpha and beta particles, which are easily blocked by air and clothing.
* **Handling:** It’s generally safe to handle Vaseline glass. However, it’s always a good idea to wash your hands after handling any antique item.
* **Storage:** Store Vaseline glass in a well-ventilated area. Avoid storing it in enclosed spaces for extended periods.
* **Concerns:** If you have concerns about the radiation emitted by Vaseline glass, consult with a health physicist or radiation safety expert.
## Conclusion: Mastering the Art of Identification
Identifying Vaseline glass requires a combination of observation, knowledge, and a bit of practice. By following the steps outlined in this guide, you can increase your chances of accurately identifying genuine Vaseline glass pieces and building a valuable collection. Remember to always be cautious and consult with experts when in doubt. With patience and persistence, you’ll soon be able to unmask the mystery of Vaseline glass and appreciate the beauty and history of this unique and fascinating glassware.
By carefully observing the color, using a UV light, examining manufacturing marks, assessing the weight, and listening to the tone, you can confidently identify true Vaseline glass and enjoy its unique beauty and history. Happy hunting!