How to Tell if Mulberry Silk is Pure: Tips and Techniques

I absolutely love the look and feel of mulberry silk. It has such a luxurious, smooth texture and a beautiful natural sheen.

However, with the popularity of silk, there are a lot of counterfeit silk fabrics out there masquerading as the real thing.

As a silk enthusiast, I’ve learned various methods for identifying whether a silk fabric is indeed genuine mulberry silk.

In this article, I’ll walk through the key characteristics of mulberry silk, tests you can conduct at home, when to seek professional authentication, and how mulberry silk compares to other silks and synthetic fabrics.

With multiple techniques under your belt and an eye for detail, you’ll be able to confidently assess the quality of mulberry silk fabric.

Physical Characteristics of Mulberry Silk

Pure mulberry silk has some distinctive physical traits in terms of handfeel, texture, drape, and luster. Becoming familiar with these tells is an important first step.

Smooth, Soft Texture

Mulberry silk should feel exceptionally smooth and soft to the touch. It will not feel rough or abrasive when you rub it gently between your fingers.

The fibers have a consistent, uniform texture without irregular lumps or slubs.

For example, high quality 19 momme mulberry silk charmeuse has an extremely soft, almost satiny texture, while a 12 momme mulberry silk habotai has a lightweight, papery smoothness.

Lightweight Drape

Mulberry silk is one of the finest natural fabrics available. It has a very lightweight, fluid drape, unlike thicker fabrics such as cotton sateen or wool.

When held up, a pure silk fabric will hang gracefully, contouring to the curves of your hand.

The exact weight and behavior varies slightly depending on the weave and momme weight, but mulberry silk generally has a refined, delicate drape.

Subtle Lustrous Sheen

One of the hallmarks of high quality mulberry silk is its natural, subtle luster. Rather than a glittery or overly shiny appearance, it should have a refined glow that catches the light softly.

The sheen comes from the prism-like structure of the silk fibers, which refract incoming light. While the surface has a bright clarity, it is not overly metallic or reflective like satin.

The glow should be evenly distributed across the silk.

The Burn Test: A Traditional Method

A time-honored way to identify silk is by carefully burning a small thread or corner of the fabric. This test allows you to observe how the fibers react to a flame.

Caution: The burn test should only be done in a safe environment while exercising great care. Have a bowl of water nearby to fully extinguish any ashes. Work over a non-flammable surface away from flammable materials.

Here is the basic procedure:

1. Carefully clip a few threads from an inconspicuous area or hidden seam allowance.
2. Hold the threads (roughly 1-2 inches) with tweezers over a non-flammable surface.
3. Light the edge with a match or lighter for 5-10 seconds.
4. Blow out the flame and observe the results.

If the threads shrink away from the flame and burn off, leaving fragile ashes, it indicates pure silk. The ash should be powdery and easily crushable between your fingers.

You may notice a burnt hair smell while burning silk threads. The flame may burn orange or yellow. Always fully extinguish ashes in water after testing.

If the threads do not shrink away or continue burning in a molten state, leaving a hard bead, it likely contains synthetic fibers and is not pure silk.

While the burn test can be useful supporting evidence, it does have some limitations:

• Not 100% definitive
• Potential safety risks
• Only confirms “silk” not mulberry silk specifically
• Small sample size

So I recommend using this traditional technique as one helpful tool among other methods.

The Water Test: Quick and Easy

Another simple way to inspect silk integrity is by observing how the fabric reacts to water. Silk and synthetic fibers have differences in water absorbency.

To perform the water test:

• Gather a few fabric swatches 1-2 inches wide, including your mulberry silk sample.
• Add a few drops of water to each swatch.
• Note differences in absorption time, spreading speed, color change and drying time.

100% mulberry silk will typically act as follows:

• Rapid absorption and spreading of water drops
• Darkening in color when wet
• Dries relatively quick within 5-15 minutes

Meanwhile, synthetic fabrics tend to have slower absorption rates. The color or sheen may look unchanged rather than darkened. And full drying can take over 30 minutes or longer.

While not definitive, the water test is a great supporting indicator of real mulberry silk. Try testing questionable silk samples against a proven high quality silk swatch.

The Touch Test: Feeling the Difference

Our sense of touch can detect subtle differences in texture between real and synthetic silk. Try rubbing between your fingers while focusing intently on the tactile qualities.

I recommend having a verified sample of mulberry silk to compare against the test fabric. Concentrate on detecting any differences in smoothness, friction and temperature regulation:

• Smoothness: Mulberry silk fibers have a uniform, round structure that enhances smoothness. Synthetics may feel rough or uneven.
• Friction: Silk generally feels soft and fluid between surfaces rather than sticky or gripping.
• Temperature: Silk adjusts quickly to match your skin temperature. Synthetics tend to feel cooler or warmer.

With practice, you can train your fingers to discern subtle distinctions. The touch test results align well with other methods. When combined, you can reliably judge silk purity.

Visual Inspection: Identifying Mulberry Silk by Eye

Close visual analysis using good lighting and magnification helps confirm many characteristics of high quality mulberry silk:

• Weave consistency: The threads should have uniform thickness and tension without loose or broken filaments. Inspect the edges for stray threads and neat seam allowances.
• Sheen distribution: Turn the silk at different angles to check for uniform luster rather than dull patches. Often poor quality silk will have uneven reflecting properties.
• Color clarity: Fine mulberry silk has rich, saturated colors without murkiness. Variegated color patterns should transition smoothly without sharp demarcations.
• Print alignment: For patterned silk, check alignment across seams so motifs line up correctly across panels indicating quality production.
• Imperfections: Use a magnifying glass to check for slubs (lumps), breaks, uneven dyeing or foreign particles that would diminish silk quality and durability.

With close observation, inconsistencies will stand out compared to uniform mulberry silk fabric. Train your eye by comparing benchmark silk samples side-by-side with the test piece.

The Ring Test: Simple Yet Effective

This clever technique uses the smooth, flowing properties of silk threads to check for polyester contaminants:

1. Cut a 1-inch wide strip of silk fabric along the grain.
2. Twist it tightly into a cord and join the ends to form a ring.
3. Smooth out the ring on a flat surface into a perfect circle.

Take a look at this:

• 100% mulberry silk will form a neat, round ring.
• Silk blended with as little as 5% polyester will resist smoothing into a hoop shape.

While not definitive alone, the ring test is extremely useful for detecting the presence of synthetic content alongside silk fibers.

Try this method with suspect fabrics as well as proven 100% mulberry silk samples.

Professional Authentication: When in Doubt

For very expensive purchases or uncertain results from home tests, consider enlisting professional silk authentication services.

Qualified labs have advanced technical equipment to analyze fabric composition and structure.

Common analysis methods include:

• Microscopic inspection
• Enzyme digestion
• Burn rate comparison
• Computerized tomography
• Spectrophotometry
• Chromatography

Reputable textile testing facilities can provide detailed authentication reports outlining the silk type, quality characteristics and processing methods.

Costs range from $50−300+ per sample depending on the depth of analysis. While an investment, definitive gradings bring peace of mind for prized silk acquisitions.

I suggest the following resources to find accredited silk testing labs:

• The Silk Association of America
• American Association of Textile Chemists and Colorists (AATCC)
• International Fabricare Institute (IFI) testing centers

Understanding the Difference: Mulberry Silk vs. Pure Silk

At this point, you may be wondering – what sets mulberry silk apart from other silk varieties to make it so coveted?

Mulberry silk comes specifically from the Bombyx mori silkworm which feeds on the leaves of mulberry trees (rather than oak or aralia).

Renowned for its exceptional smoothness, luster, and durability, it is the most common silkworm variety used in silk production.

Meanwhile, “pure silk” refers more generally to silk derived from any silkworm species. The various types have differing quality characteristics:

• Tussah silk: Shaggier texture with uneven luster from oak-eating Antheraea silkworms
• Eri silk: Soft but less durable silk from the Attacus ricini silkworms
• Spider silk: Extremely fine but difficult to harvest at scale

So while other silk varieties have attractive qualities, mulberry silk stands above them all as the gold standard for its unparalleled aesthetic properties and versatility.

If you’re buying silk, knowing how mulberry silk is graded is essential.

Real Silk vs. Fake Silk: Key Differences

With silk’s popularity, many textile manufacturers attempt to mimic its smooth feel and beautiful drape.

But there are noticeable differences between real silk and synthetic “silk-like” fabrics.

Here is a comparison overview:

Common synthetic silk-like fabrics include polyester, nylon, rayon, acetate, and synthetic blends.

With a discerning eye, you can identify fakes through stiffness, overly-perfect sheen, greater thickness, and irregular drape.

While synthetics have come a long way, they cannot truly match the hypnotic glow and fluid movement of genuine mulberry silk!

Knowing the difference between authentic and imitation mulberry silk has saved me from many bad purchases.

Conclusions

I hope these tips give you confidence in assessing the authenticity of mulberry silk fabric.

By using a combination of techniques – from burn tests to professional authentication – you can make accurate judgments.

With practice, your senses will attune to the telltale refinements of quality silk. While counterfeits abound, trust your hands, eyes and intuition.

Seek out reputable textile suppliers dedicated to ethical, sustainable silk production. Cherish the beauty and luxury of this timeless, natural fabric.