Its a never-ending question, which Speedmaster Professional should I buy? The one with sapphire or a model with Hesalite crystal? And then theres not just a single right answer. Both have their own advantages. But heres why every Speedmaster fan should at least have one model in their collection with a Hesalite crystal.Technology advances. Man developed new solutions for watchmaking constructions. Thats quite understandable. New lubricants brought a better lubrification lifespan. New materials ensured better anti-magnetic properties. Different constructions made longer power reserves possible. And thats not the end of the list.A Speedmaster Professional with sapphire crystalWhy choose an Omega Speedmaster Professional with Hesalite crystal?The original Omega Speedmaster in 1957 was equipped with acrylic or more commonly, plastic crystal*. Just like many other sports watches and chronographs of that era. The main reason to use plastic instead of mineral glass was the resistance to shattering. On heavy impact more commonly sustained by tool watches rather than dress watches an acrylic crystal will crack, not shatter. Not only are tool watches more likely to be hit, but the environment in which they are used is also often more sensitive to glass splinters flying around. Imagine the many dangers posed by loose glass splinters flying around a cockpit environment in an airplane or space rocket?* To use the word crystal for the top glass, or lens, of a watch is a bit confusing. Crystal is a totally different material from plastic. But, one way or another, the word crystal or glass is used to determine the part that transparently protects the dial and hands. Whatever material its made of.Sapphire (left) vs Hesalite (right)What exactly is Hesalite?As we can see,?Omega uses the term Hesalite to describe Speedmaster crystals. But what exactly is Hesalite? Well, Hesalite is a transparent thermoplastic, or PMMA Poly Methyl Meth Acrylate.PMMA comes from different producers, which might have slightly different optical and or mechanical properties. But to be honest, basically, all PMMAs are the same. The difference is often caused by a producer of the PMMA using a tradename. So if we see Perspex, Plexiglass, Lucite, Sumiplex, or Hesalite being used, were looking at different commercial compositions of PMMA produced by different manufacturers. The Hesalite brand is owned by Topacryl in Switzerland.Technology advancesOne of the technical developments in watchmaking was the use of sapphire for the top crystal. Sapphire is also a natural gemstone but has little to do with a sapphire watch glass. The sapphire used for watch glasses is a hard, transparent material made of crystallizing pure aluminum oxide at very high temperatures. The only thing the two types of sapphire have in common is that synthetic sapphire has the same hardness as natural sapphire gemstones, but without the color that gives the gems their attractiveness.Sapphire crystalA sapphire crystal is due to its difficult production process much more expensive than one made from transparent thermoplastic. As said, a sapphire crystal is tough and is almost impossible to scratch. Technically that sounds promising and preferable for a daily worn watch. Therefore, in most cases, its a desirable choice. Except for that 1% using a watch in an environment where the tiny chance of scattering a watchs crystal isnt desirable or allowed, it is technically the best solution for most people. But is it the best solution for a hardcore Speedmaster fan?Hesalite is not an intellectual choice.I dont think so. Technically, probably yes. But then as well, wouldnt an Apple Watch technically be a better solution than an Omega Speedmaster Professional? Probably also yes. But, in my opinion, fans dont wear nor buy their Speedmasters for intellectual reasons. Wed be going too far to discuss why people are attracted by certain types of watches here. But in the end, luckily, most of the reasons come down to feeling and arent intellectual choices.HesaliteAnd thats why I think any Speedmaster fan should at least have one Speedy with a Hesalite crystal. It definitely looks different, and it gives a different experience when wearing the watch. The difference in appearance is one reason, but the historic notion also helps. This is how Speedmasters are used professionally; this is how they were meant to be. Perfect for a specific application. The real deal.But itll scratch.Yes, your Hesalite crystal will scratch easier than a sapphire one. And then, so what? Of course, I can imagine that if you just spent almost 5,000 on something that you love, you dont like to have it scratched. Thatd hurt. But Im sure that the joy that a Hesalite Speedmaster will give you will outclass the disaster of scratching your crystal. I mean, its just a plastic crystal. Its meant to be scratched; it protects your dial and hands. Scratches dont mean much harm to your watch or your wallet if you want to have it replaced. And, instead, they imbue a watch with a priceless character.As the pictures will make clear, I use a Speedmaster with Hesalite crystal as a beater. That can not only be told from the Hesalite but from the condition of the whole watch as well. And I like it that way. I didnt buy this one brand new. I bought it from a commercial airline pilot who used it as a tool until he retired. This watch has flown all over the world for decades. It has knocked on more instruments, doors, and whatnot than many of us could hope to clatter into over a lifetime. At once, an extra scratch on the Hesalite isnt a disaster anymore; its a battle scar. It means its my watch, and Ive shared experiences with it.How easily will Hesalite scratch?I know there are a few sorts of pencil tests, but theres one to indicate the hardness of Hesalite as well. Lead pencils exist in various hardness. They normally range from 6B very soft to 9H very hard. Only the hardest type of pencil, 9H, can scratch a Hesalite crystal.And what is against sapphire crystal?As mentioned, besides for historical reasons, a sapphire will give your Speedmaster Professional a different look. The dial will look slightly clearer and sharper, specifically compared to a watch with a Hesalite crystal that has been worn for a while. Is that bad? No, its not bad, but different, and it will make your Speedmaster look a bit overly perfect. Theres another point, however, and thats the visual deformation of the dial.