Arnold & Son has consistently carved out a distinct niche in the crowded landscape of high horology by adhering to a specific design philosophy that marries British heritage with Swiss precision. The release of the Time Pyramid 42.5 Malachite represents a continuation of this journey, reinforcing the brand's reputation for creating mechanical sculptures that tell time. This latest iteration does not merely present a new colorway; it fundamentally alters the visual weight and personality of the Time Pyramid by introducing a hard stone backdrop that contrasts vividly with the industrial architecture of the skeletonized movement. Available in two strictly limited variations, one encased in warm 5N red gold and the other in the cool, understated luster of platinum, the watch offers a masterclass in transparency, symmetry, and material contrast.
The immediate visual impact of the Time Pyramid 42.5 Malachite is one of suspended animation. Unlike traditional skeleton watches that often look cluttered or chaotic, the Time Pyramid is defined by a rigorous, almost architectural order. The movement, the A&S1615, was not adapted from an existing calibre but was built from the ground up specifically to fit this case and this concept. The result is a triangular structure that mimics the shape of a pyramid, with the escapement located at the very apex of the dial at the 12 o'clock position. This layout is visually arresting because it inverts the typical expectations of movement construction, placing the most active and oscillating component—the balance wheel—front and center at the top of the display, turning the heartbeat of the watch into the primary focal point.
Courtesy of Arnold & Son
Supporting this horological pyramid are two mainspring barrels located at the base of the movement, positioned at 5 o'clock and 7 o'clock. These barrels provide a visual anchor, creating a wide foundation that tapers upward through the gear train. This linear arrangement is a direct nod to the brand’s historical roots, specifically drawing inspiration from the regulators and standing clocks created by John Roger Arnold in the mid-19th century. In those historical clocks, the vertical disparity of components was a functional necessity for precision and ease of service. In the Time Pyramid 42.5, it becomes an aesthetic choice that celebrates the mechanical honesty of the device. There is no dial in the traditional sense to hide the works; the mechanics are the aesthetic.
The introduction of malachite into this equation changes the entire character of the timepiece. In previous iterations, the transparency of the Time Pyramid was absolute, with the wearer able to see through the watch to their own wrist. Here, Arnold & Son has chosen to close the back with a disc of malachite, a copper carbonate hydroxide mineral known for its intense, banded green hues. The choice of malachite is particularly effective because of the stone’s natural striations. The vertical bands of light and dark green found in the stone complement the verticality of the movement’s gear train. It provides a rich, opaque canvas against which the rhodium-plated and NAC-treated grey bridges can stand out. The stone acts as a theatrical backdrop, highlighting the depth of the three-dimensional movement and preventing the visual confusion that can sometimes occur with fully transparent sapphire casebacks.
When holding the watch, or observing it closely, one notices that the malachite is not just a flat surface but a texture that interacts with light. The stone is renowned in lapidary circles for its ability to take a high polish, but it also retains a natural, organic feel that contrasts with the clinical perfection of the machined metal parts. The green is deep, often described as imperial or forest green, and it brings a sense of old-world luxury that pairs exceptionally well with both case materials. In the red gold version, the green and gold combination evokes a classic, regal palette, while the platinum version offers a sharper, more modern contrast, where the silver tones of the case and movement let the green take absolute center stage without fighting for warmth.
The case itself measures 42.5 millimeters in diameter, a size that allows the expansive movement to breathe without feeling dainty. Despite the complexity of the internal mechanics, the watch maintains a relatively slender profile with a thickness of just 10.72 millimeters. This includes the domed sapphire crystal, which adds a bit of height but also provides a vintage aesthetic and minimizes optical distortion. The bezel is kept intentionally thin. This is a crucial design decision, as a thick bezel would detract from the "floating" effect of the movement. By minimizing the metal ring around the dial, the eye is drawn immediately inward to the interplay of gears and stone. The lugs are short and curved, ensuring that the watch hugs the wrist comfortably despite its moderate size.
Courtesy of Arnold & Son
One of the most defining features of the Time Pyramid’s case design is the location of the crown. Unlike the vast majority of wristwatches where the crown is situated at 3 o'clock, Arnold & Son has placed the crown at the 6 o'clock position. This is not merely an affectation but a requirement of the movement’s symmetry. Because the barrels are located at the bottom and the gear train runs vertically, placing the keyless works and winding mechanism at the bottom maintains the perfect left-right balance of the caliber. It also offers an ergonomic benefit; the crown does not dig into the back of the hand when the wrist is bent. Visually, it cleans up the flanks of the case, leaving the sides perfectly smooth and uninterrupted, further enhancing the sculptural quality of the object.
The dial for the hours and minutes is a sub-assembly located centrally, slightly below the canon pinion. It is made of white opal, a material that offers a milky, translucent luminosity. The choice of white opal is clever; it ensures legibility against the complex background. If the dial were skeletonized or metallic, the blued hands might get lost in the visual noise of the bridges and gears. The opal provides a clean, stark background for the heat-blued hands, ensuring that reading the time remains intuitive. The hands themselves are arrow-tipped and polished, catching the light as they sweep over the Roman numerals printed on the opal ring.
Flanking the opal hour dial are two power reserve indicators, located at the 9 o'clock and 3 o'clock positions. These are not standard indicators; they are serpentine hands that trace small arcs on the sapphire crystal itself. The existence of two separate power reserve displays is a direct result of the movement’s dual-barrel architecture. The calibre A&S1615 utilizes a series-winding system. This means that as you wind the crown, the first barrel winds the second barrel. The indicators show the state of wind for each barrel individually. As the watch runs, the energy transfers from one barrel to the other, keeping the torque curve relatively flat. Seeing one hand drop while the other retains its position, or watching them interact during the winding process, adds a dynamic layer of interaction to the ownership experience. It visualizes the flow of energy in a way few other watches do.
The movement finishing is executed to the high standards one expects from a top-tier Swiss manufacture. The main plate and bridges are treated with NAC, a galvanic coating that gives them a slate-grey, anthracite color. This darker tone is instrumental in creating contrast. If the bridges were standard brass or bright rhodium, they might blend too much with the platinum case or clash with the red gold. The dark grey serves as a neutral middle ground that allows the gold wheels and the blued screws to pop. The bridges are finished with vertical Côtes de Genève stripes, which align with the linear layout of the gear train. The edges are manually chamfered and polished, catching the light and defining the geometric boundaries of each component. Even the wheels are circular satin-finished, showing attention to detail even in the parts that are constantly in motion.
Courtesy of Arnold & Son
The technical prowess of the A&S1615 calibre extends beyond its architecture. Operating at a frequency of 3 Hertz, or 21,600 vibrations per hour, the movement strikes a balance between precision and component longevity. The large balance wheel, visible at the top, oscillates with a mesmerizing rhythm. The use of a lower frequency is often preferred in such architectural movements as it allows the eye to better appreciate the breathing of the hairspring. With a power reserve of 90 hours, the watch offers nearly four days of autonomy. This is significant for a manual-wind watch, reducing the need for daily winding. The torque management provided by the dual barrels ensures that the amplitude of the balance wheel remains stable throughout the majority of the power reserve, contributing to better isochronism and overall timekeeping performance.
The malachite disc on the caseback is not completely solid; it is lined with a sapphire crystal to protect the stone and the movement. This construction technique allows the observer to view the movement from the back as well, although the front view is admittedly the star of the show. However, the expanse of green on the back, framed by the gold or platinum ring of the caseback, creates a feeling of solidity and substance. It reminds the owner that they are wearing a piece of the earth, a slice of geology that has been refined and integrated into a machine. The belief that malachite is a protective stone, guarding against the "evil eye" and promoting balance, fits poetically with a watch so obsessed with mechanical symmetry.
Both versions of the watch are fitted with a hand-stitched alligator leather strap in a shade Arnold & Son calls "imperial green." This strap color is carefully matched to the malachite dial, creating a cohesive aesthetic package. The leather is sourced from high-quality hides, featuring large square scales that suggest durability and luxury. The stitching is tone-on-tone, keeping the look refined and dressy. The strap is secured to the wrist by a pin buckle in the matching case metal—18-carat red gold or platinum. The buckle design is simple and classic, featuring the Arnold & Son logo, and does not distract from the watch head.
The distinction between the two limited editions is primarily tonal. The 18-carat 5N red gold model feels warmer, more vintage, and perhaps a bit more ostentatious. The red tones of the gold amplify the saturation of the green malachite, making the watch feel like a piece of royal jewelry. The golden gear train wheels blend harmoniously with the case, creating a unified warm aesthetic. Conversely, the platinum version is icy and sharp. The white metal creates a high-contrast frame for the dark grey movement and the deep green stone. It feels more technical, more architectural, and arguably more contemporary. The platinum alloy, Pt 950, is dense and heavy, giving the watch a significant presence on the wrist that speaks to its value and rarity.
The skeletonization process used in the Time Pyramid is extensive. The main plate is heavily open-worked, removing as much material as possible without compromising structural integrity. This leaves the viewer with a clear sightline through the various levels of the mechanism. You can trace the transmission of power from the winding stem at 6 o'clock, through the keyless works, into the two barrels, up the center wheel, through the third and fourth wheels, and finally to the escape wheel and balance at 12 o'clock. This transparency allows for an educational experience; one can literally learn how a watch works simply by observing the Time Pyramid in operation.
Courtesy of Arnold & Son
The choice of malachite as a material also introduces a degree of uniqueness to each piece. Since malachite is a natural stone formed by copper deposits, the banding and patterning are random and unique to each slice. No two watches in this limited run will look exactly the same. Some may have tight, concentric bands, while others might feature broader, straighter strokes of green. This organic variation provides a nice counterpoint to the extreme precision of the CNC-machined and hand-finished metal components. It creates a dialogue between the perfection of engineering and the imperfect beauty of nature.
In terms of wearability, the 42.5mm case sits flat on the wrist due to the curvature of the lugs. The placement of the crown at 6 o'clock removes the potential for digging into the wrist, which is a common complaint with larger watches featuring prominent crowns at 3 o'clock. The lack of a rotor (since it is a manual wind movement) keeps the watch relatively light and thin compared to an automatic counterpart, although the platinum version will naturally have a reassuring heft. The manual winding interaction is also a key part of the ownership experience. Winding the watch from the bottom feels different; it requires a different grip and motion, serving as a tactile reminder of the unique engine inside.
The interplay of circles is another design motif that becomes apparent upon closer inspection. The round case, the round barrels, the round balance wheel, the round opal dial, and the round gears all interact within the triangular, pyramidal layout. This geometric tension between the triangle and the circle is pleasing to the human eye, which naturally seeks out patterns and symmetry. Arnold & Son has mastered this geometry, ensuring that despite the negative space and open-working, the watch never feels empty. It feels purposeful, with every millimeter of space utilized to either display a mechanic or reveal the stunning green backdrop.
The technical specifications regarding water resistance are standard for a dress watch of this caliber. Rated at 3 bar, or 30 meters, the watch is splash-resistant but certainly not designed for swimming or aquatic activities. This is entirely appropriate given the leather strap and the delicate nature of the movement and the malachite stone. The focus here is on chronometry and aesthetics, not rugged durability. The anti-reflective coating on both sides of the sapphire crystal is a practical addition that is often overlooked. By eliminating glare, the brand ensures that the view of the movement and the stone remains unobstructed even under harsh lighting conditions.
The rarity of these timepieces cannot be overstated. With the production strictly limited to just eight pieces in red gold and eight pieces in platinum, these are not watches that will be seen frequently in the wild. They are destined for the collections of serious horological enthusiasts who appreciate the specific blend of British history and Swiss manufacturing that Arnold & Son provides. The limitation is likely due in part to the difficulty of working with malachite, which can be brittle and difficult to machine to such thin tolerances without cracking, as well as the labor-intensive nature of hand-finishing the movement bridges.
Courtesy of Arnold & Son
Ultimately, the Arnold & Son Time Pyramid 42.5 Malachite is a study in contrasts. It contrasts the ancient, natural beauty of malachite with the modern, industrial beauty of a NAC-treated movement. It contrasts the vertical linearity of the gear train with the rotational motion of the wheels. It contrasts the warmth of gold with the cool of platinum. It is a timepiece that respects the history of John Arnold’s quest for marine chronometer precision while embracing a visual language that is distinctly contemporary. It does not look like a vintage watch, yet it could not exist without the history that preceded it.
For those interested in acquiring one of these rare mechanical sculptures, the financial barrier to entry reflects the exclusivity and materials used. The 18-carat 5N red gold edition (Reference 1TPER.F01A.C1250A) is priced at $56,000. For the collector who prefers the stealth wealth and physical density of platinum (Reference 1TPEX.F01A.C1250X), the price steps up to $69,900. Given the limitation of only eight pieces for each metal, availability is expected to be scarce, likely restricted to authorized boutiques and key retail partners. These prices position the Time Pyramid 42.5 Malachite squarely in the upper echelons of independent watchmaking, offering a value proposition based on unique architecture, precious materials, and genuine scarcity.
Case: 42.5mm diameter, 10.72mm thickness; available in 18-carat 5N red gold or platinum (Pt 950); domed sapphire crystal with anti-reflective coating on both sides; case back features a malachite disc lined with sapphire crystal and anti-reflective coating; winding crown positioned at 6 o'clock; water-resistant to 3 bar (30 meters).
Movement: Calibre A&S1615; manual winding mechanical movement; skeletonized pyramid architecture; 27 jewels; 37.60mm diameter, 4.40mm thickness; 90-hour power reserve via double barrels; frequency of 3 Hz (21,600 vph); NAC-treated main plate and bridges with vertical Côtes de Genève stripes and hand-chamfered edges; golden finished wheels; blued screws.
Dial: White opal off-centered dial for hours and minutes; blued arrow-tipped hands; Roman numerals; dual power reserve indicators printed on the sapphire crystal; malachite stone backdrop visible through the open-worked movement.
Strap: Imperial green alligator leather; hand-stitched; pin buckle in matching 18-carat 5N red gold or platinum (Pt 950).
Price: $56,000 (Red Gold) / $69,900 (Platinum)
Reference Number: 1TPER.F01A.C1250A (Red Gold) / 1TPEX.F01A.C1250X (Platinum)
Notes: Limited edition of 8 pieces for each case material. The movement architecture is inspired by antique regulators made by John Roger Arnold.