Portmeirion Pottery Moss Agate Design Vinegar Bottle And Stopper, SM4-MA19
Portmeirion Pottery

An extraordinarily rare Portmeirion Moss Agate factory trial vinegar bottle - a unique experimental piece testing Susan Williams-Ellis's innovative design on an alternative colourway. The ultimate Holy Grail for serious Portmeirion collectors.

This is not just a rare Moss Agate piece - this is a factory trial, making it exponentially rarer than even standard production Moss Agate, which itself is considered the rarest of all Susan Williams-Ellis's designs. Factory trials represent Susan's creative process in action and are virtually never available to collectors.

What Makes This Trial Piece Unique

While standard Moss Agate features black transfers enriched with 22-carat gold lustre on a white or cream ground, this experimental vinegar bottle tests a completely different approach: black Moss Agate transfers applied over a rich terracotta brown glaze. This striking alternative colourway demonstrates Susan's exploration of how the design would work on different ground colours.

Factory trials like this were created in extremely limited numbers - often just one or two examples - to test colour combinations, glaze compatibility, and visual impact before committing to production. Most trial pieces were destroyed or remain in factory archives, making those that survive museum-quality artifacts of the design process.

The fact that this trial piece has survived and is now available to collectors is exceptional. It offers a unique glimpse into Susan Williams-Ellis's creative workshop and her perfectionist approach to developing the Moss Agate design.

Condition & Authentication

Overall Condition: Excellent for a factory trial piece of this age and significance. The black transfer work is crisp and well-defined. The terracotta glaze is rich and even throughout.

Noted Imperfections:

• Small chip to the base edge of the bottle (not visible when displayed)
• Minor mark on the neck rim (consistent with stopper use over time)

These very minor flaws are typical of trial pieces which were working samples rather than finished production items. They in no way diminish the historical significance or collectability of this extraordinary piece.

Complete with Original Stopper: Both bottle and matching stopper are present, which is rare for items of this age.

Certificate: Supplied with a signed certificate of authenticity by Stephen McKay, internationally recognised Portmeirion expert and author.

Why This Trial Piece Matters

Factory trials offer collectors something production pieces cannot: a direct connection to the designer's creative process. This vinegar bottle represents an experimental moment in Susan Williams-Ellis's studio - testing whether the sophisticated Moss Agate design could work on darker ground colours to create different aesthetic effects.

The terracotta colourway creates a warmer, earthier feel compared to the cool elegance of the standard white ground with gold enrichment. It demonstrates Susan's willingness to push boundaries and explore multiple directions for her most complex design.

For advanced Portmeirion collectors, factory trials represent the pinnacle of collecting - tangible evidence of Susan's design genius and experimental approach.

Investment & Collectability

This is an investment-grade piece for the most serious Portmeirion collectors. Factory trial pieces:

• Are exponentially rarer than production items
• Document the design and development process
• Represent museum-quality provenance
• Rarely appear on the market
• Command premium prices due to their unique status

Finding any Moss Agate piece is compared to finding the Holy Grail. Finding a factory trial in an alternative colourway is beyond exceptional - it may be a once-in-a-lifetime opportunity.

An unrepeatable opportunity to acquire one of the rarest and most historically significant pieces of Portmeirion pottery ever offered.

Approx Dimensions:-

8.5 in (21.5 cm) tall

2.25 in (6 cm) diam 

Moss Agate

Shortly after the creation of 'Malachite', Susan Williams-Ellis's ground-breaking, hand painted design of the semi-precious gemstone of the same name, she conjured up an astonishing design based on another gemstone called 'Moss Agate', and this is what she called her design.  Susan researched her idea using old books on geology which had some images of actual agate samples. When the stone is forming, impurities work their way into the material, naturally causing imperfections and marks; some resembling leaf, plant and tree-like patterns and sometimes ferns and firework displays. Some of these stones were, and are still, highly prized and are cut into cameos and cabochons for the jewellery trade. These natural and unusual forms fascinated Susan and she began designing a pattern based on what she had seen. She drew a background pattern consisting of noughts, crosses and dots which then had individual illustrations of cameos of agate scattered over it. This pattern was then engraved onto a copper sheet, from which a delicately inked transfer was produced. This transfer was placed onto the item to be decorated, mainly straight sided items as the pattern worked best on these. Rich, 22 carat gold liquid lustre, 'best gold', was applied to the cameos. During her trials, Susan noticed that the part of the transfer that remained under the gold lustre, partially resisted the gold and peeked through once it was fired and burnished, giving a ghostly but three dimensional appearance. The little cameos took on a whole new appearance, looking more like real cameos than Susan had ever hoped for. In fact, Susan had invented a new technique all together! Despite the excitement of this new design, the process was long, difficult and incredibly expensive, and remains the most costly and rare of all Susan's designs. Few items were made and mostly were done as gifts for family and friends, as full production was financially out of the question. Most of the items made were on Gray's standard shapes such as lidded jars, tapered mugs, apothecary jars, goblets and a few coffee sets made on a bone china body by Tuscan. Richly gilded and highly decorative, these rare and unusual pieces are normally found in excellent condition, having been kept in cabinets all of their lives. Finding a piece these days is like finding the 'Holy Grail'!