A WatchCarefully comparative review of two
vintage watches with Tiger-Eye stone dials

Rado Diastar & Technos Borazon

by C. Bradley Jacobs

Rado has long been recognized as a leader among watch brands. Their ground-breaking designs and their innovation in the use of hard metal and ceramics to produce scratch-resistant cases have few peers. Having accomplished so much over the past four decades or more, it is understandable that many other brands have adapted Rado designs and methods of construction for their own products. In some cases, a delicate balance is stuck between homage to the innovator and introduction of an original design. In other cases, the intent to copy the original and insinuate a new, similar product into an existing market is clear. Without attributing to the brand any motives, I have chosen to compare a Technos watch to a Rado watch in this review of two interesting 1970s products:

The first watch, considered a benchmark by many collectors and historians, is the Rado DiaStar. First introduced in 1962, this model featured (and still does) a case with a prominent oval bezel made of sintered tungsten-carbide. The use of this material was heavily promoted as rendering the watch scratch-proof, and the model became an icon of design—one often copied and re-interpreted, even until today. The example being examined for the purposes of this review is a ca. 1970s DiaStar Magic, reference DiaStar 13G. It is a gold-tone model of the usual basic shape and it features a faceted sapphire crystal, automatic day/date movement by ETA, and a dial made of stone. In the 1970s-1980s Rado, and many other companies, marketed watches with stone components (usually dials, though Tissot and some others produced stone watch cases as well) which were not a large proportion of their production, but were made in enough varieties to be a collectible theme of their own. The DiaStar shown here features a dial of tiger-eye stone.

The second watch is of, shall we say, a similar style. It is a Borazon model from Technos watch company, a Brazil-based assembler of Swiss-made components. Again, this watch has a hard-metal case, faceted sapphire crystal, ETA automatic movement, and tiger-eye stone dial. The similarities are obvious and, presumably, intentional. However, this is not a mere copy of a Rado icon. This review will focus on some of the individual elements of the Technos that give it a personality of its own, even when displayed side-by-side with the DiaStar.

The method of comparison used for this review is both objective and subjective. I will describe the elements of each watch with as little emotion or opinion as possible, but then draw a conclusion of a subjective nature. When appropriate, I will declare one watch to have the edge over the other. I trust that the reader will not be offended. Due to the history of Rado, I consider it to be the more “established” brand, and I will conduct the comparison by describing the DiaStar first and then explaining how the Technos measures up (or fails to) against the “original.”


Though the obvious place to begin comparing a DiaStar with similar watches is the case, these watches are exceptional for one reason, and that is reason enough to look first at their dials.

First, some disclaimers: These watches, both being in good running condition and fairly well sealed, have not been completely disassembled for the purpose of this review. No in-depth descriptions of the method of construction of each dial will be given, nor will they necessarily be closely photographed. All comments on quality are the opinion of the reviewer who is not an expert in mineral specimens, nor in the making of watch dials.

The dial of the Rado is of typical DiaStar configuration. It has a day/date aperture at 6:00 and bold 3-dimensional markers for the hours (more on this below). One noteworthy feature is lacking: the anchor logo that spins on a jewel-like bearing set into the dial. This has been a regular feature of Rado automatic watches since 1962, but is often replaced with a printed logo on watches with stone dials. Communication with Rado has indicated just what one would expect—that the addition of any extra perforations in the stone (aside from the day/date window and the central hole for the hands) would endanger its integrity. As a result, on this watch we see that the Rado logo, brand name, and model name are printed in crisp, legible white paint. Most other DiaStar models feature applied logos and names. The printed elements here are appropriate, though, for any additional 3-dimensional elements would distract from the main feature of the dial: the reflective/refractive quality of the stone.

The stone used for this particular dial appears to be of good quality. There are no visible interruptions in the pattern of striations, nor are there cracks. Light is captured and reflected in a way that makes the dial appears very bright and lively, without being flashy like polished gold would be. Indeed, the stone, though very animated as the angle of light changes, actually imparts a mellowness, subduing the overall bright presentation of the watch’s gold-tone case and bracelet.

The dial of the Technos was created with a much less bright slice of stone. At a glance it appears to be more like brushed brass than tiger-eye, but with a close examination, and sufficient light, it is clearly tiger-eye. Unlike the stone of the Rado dial, the range of colors in the Technos tiger-eye is more monochromatic. The striations are much less obvious and, with the position of the grain of the stone being perpendicular to the parallel facets of the crystal, it is difficult at a glance to recognize their orientation. For the sake of this review, the dial and movement were removed from the Technos for photography:

The printing upon the Technos dial is a copper- or gold-tone and thus the entire presentation is rather monochromatic. In certain light the printing is almost invisible, an effect which accentuates the stone but can be annoying when one tries to read the text.

I cannot determine which is the higher quality or rarer piece of stone, but I would give higher marks to Rado for choosing one that is more pleasing to my eye. From a quality perspective, it is clear that Rado wins this round. Their characteristic beveled window frame is far more attractive than the unadorned date aperture of the Technos—an element that seems to be almost an afterthought. The seam between the dial and the chapter ring are far cleaner on the Rado than the Technos, though this is not obvious during normal use without magnification.

Markers and Hands

Rado chose to use bold 3-D gold markers filled with white paint, which nicely matches the white painted dial elements such as those mentioned above, but also included printed white minute markers on the stone. The gold hands are pointed & polished, beveled & grooved, and feature openings which are filled with luminous paint to match the luminous dots applied to the dial before each raised hour marker. The minute and seconds hands reach very close to the appropriate chapter and the hour hand is of a reasonable and proportionate length. All of these elements are of good quality and, though the luminosity has declined in the decades since it was produced, the readability of the interface is surprisingly good for such a busy and decorative construction.

The Technos markers are also 3-dimensional and gold, but are topped

with small black bars which match the printed black minute chapter on the gold ring at the perimeter of the dial. In sufficient light, this is a pleasing combination but in darker situations, proves much harder to read than the Rado. Gold beveled hands with black fill continue the theme. These are not of the same elaborate design as those of the Rado—almost imperceptible angles and shorter length (and the lack of an extended minute chapter printed on the stone dial) make a weaker overall impression than on the DiaStar.


Both watches are powered by ETA 25-jewel 2824 variants. The Rado’s is gilt while the Technos’s is nickel plated. Both are running well years after having been assembled and with their service histories unknown. Cursory examinations of each watch and movement reveal that the Rado has probably not been used much nor serviced in its lifetime. The Technos has definitely been opened, perhaps for service. It shows some wear on the back and is also missing part of a marker that would be loose inside if the watch had not been opened and this item removed. It would be unfair to grade either watch on the accuracy of the movement, since neither has recently been serviced (to my knowledge), though the Rado has been running within a second or so per day for 2-3 weeks. Similarly, it would be unfair to give the Rado higher marks for having a day display, though I find the Rado’s 6:00 placement of the day-date window symmetric and more pleasing than the 3:00 date aperture on the Technos. It may be fair simply to acknowledge that both brands chose solid, proven movements which were the standard of their day for their price range.

Case and Bracelet

Rado’s DiaStar case is an icon. However, it is perceived by many watch collectors as having an ungainly bulk, and an unimaginative shape. The explanation for these features probably dates back to the early days of the DiaStar’s design. Mr. Marc Lederrey, chief designer for Rado in the early 1960s, was the first to explore the use of unusual alloys and space-age materials in watch case making. At that time, the fragility of the materials and the limited capabilities of the production machinery meant that only a simple bezel could be produced. A minimal number of steps was preferred, as a more complex design might increase the risk of waste during manufacturing and finishing. Thus was born the oval DiaStar and, though many variations have been produced since (eg, the DiaMaster and Balboa series), it is this original design that comes to mind when Rado’s tungsten-carbide bezels are discussed.

With this particular example of the Technos Borazon, we see that some liberties were taken with the original idea of the scratch-proof bezel. Many additional facets are included and, though the vestiges of the original oval design are present, the result is a watch that appears to be thinner and more svelte. Also, this new shape does more to identify this watch as not being a product of Rado than any other element. The origin of the idea is not completely disguised, but the finished product has more of its own personality than most DiaStar derivatives.

Both watches included folded-steel bracelets with fold-over clasps. The Rado bracelet was produced and marked by noted supplier Novavit S. A. (NSA) while the Technos bracelet is unsigned. Both are proper for this style of watch, even if their originality to each piece cannot be verified. Typically, Rado and Technos and many other brands used bracelets of this type, the clasps of which were stamped or engraved with the company name and/or logo. Signed crowns were also the norm for these brands and the Rado’s is gold-plated with the anchor logo. The Technos would have a steel crown with a raised “T” although this example appears to have an unsigned replacement.

The cases of each watch are massive and have screw-on backs with the company logo and a case number engraved. The Rado is 13 mm thick x 35 mm wide and 42 mm long. The Technos measures 12 x 35 x 38. The choice of which style of case is preferable is, obviously, a personal one. In the context of this comparison, it may be fair only to note that each timepiece’s case is quite appropriate for this style of dial and the era in which they were produced.


These are both uncommon watches, and are unlikely to both be the subject of a buyer’s choice at the counter of his favorite watch seller, so this review is much less one of practicality than of historical comparison. Other brands offered dials of stone, and tungsten-carbide bezels, so this is not even a comprehensive historical review of all the similar models available to an intrepid collector. However, as a comparison of an innovator’s product with a piece clearly designed in the same vein, I hope it gives the reader some perspective on what makes a Rado a quality watch that often commands a large premium over its imitators.

My brief experience with each of these watches has left me impressed with both. This DiaStar Magic is something of a collector’s item—the extent of it’s rarity has yet to be determined, but it is in fabulous condition and is remarkable as an example of a style of dial that has not been produced by Rado in two decades or more. The Technos, is a fine example of a watch, and brand, that is very uncommon in the United States. Technos has traditionally not marketed watches in the USA and this may be another example of a brand that has reached our shores only recently as a result of the World Wide Web. Research into their history and their current product line shows that they continue to create watches based upon influential designs of other brands, yet they also produce some designs that are clearly their own. In this regard, perhaps they are akin to Invicta or MarcelloC—brands which have their own rabid devotees and detractors.

In general this Technos Borazon is a difficult watch to read except in good light. As a piece of jewelry, it is lovely, though not so much as the Rado. As an example of modern design it is eye-catching and harmonious, though not so much as the Rado. Although the Borazon’s case shape is a pleasing alternative to that of the typically bulbous DiaStar, this is not enough to make up for a host of minor deficiencies elsewhere in design and quality—the latter being the decisive criterion. It is interesting to note, that the bezels of both watches are in remarkable condition roughly thirty years after they were manufactured. Tungsten-carbide cases are not entirely scratch-proof--I have examples that are heavily scuffed--but when given appropriate care, they can certainly look like new for years.


Additional comments, etc...

Subtle things Rado did right:

  • Align the facets of the crystal with the striations of the stone.
  • Avoid dark colors on the dial.
  • Pay attention to fine details such as hands and markers.

Improvements Technos made on a classic:

  • Additional facets on the case lend a slimming effect to a case style that has always been bulbous.
  • Silver-tone case finish is more like steel or white gold than is the blue-grey of traditional Rado tungsten-carbide bezels.


Other examples of Technos Tiger-Eye dials:

For more watch articles by C. Bradley Jacobs, visit:

Click here to return to the index of articles at WatchCarefully.com

If you've read this far, you must be a fan of Rado and I invite you to visit the Rado Discussion Forum.
Text and images: © C. Bradley Jacobs and WatchCarefully.com, unless otherwise credited