No caso desse Seiko, realmente não é safira, mas sim um composto diferente de cristal, que a Seiko batizou de HARDLEX.
Sobre o Hardlex, recuperei as postagens abaixo de nossos amigos foristas:
ADRIANO: « Resposta #4 Online: 12 Março 2011 às 22:38:39 »
Minha experiência é diferente. O Hardlex risca, mas bem menos que os minerais comuns. Já dei cada porrada em Hardlex, que riscou, mas se fosse mineral comum, tinha detonado. Eu tinha uma tabela que dizia a dureza do Hardlex, não lembro onde foi parar. Lembro que a dureza dele é 7 na escala Mohs. Do mineral comum acho que é 5.
O que muda é a composição, que contém boro, se não me engano, além do método de produção ser diferente também.
Abraços!
Adriano
FALCO: « Resposta #5 Online: 13 Março 2011 às 00:06:41 »
Talvez seja melhor "ouvir" do próprio Tokunaga:
"
The materials currently used as watch glass and its main characteristics are shown in the following table.
Since the acrylic resin (1) has soft hardness and a heat-resistant temperature is very low, concerning the glass of PROSPEX watches which have high durability performance, such as a MARINEMASTER of this question, we couldn't use acrylic glass in which a lot of scratches and deformation are occurred on the surface.
Although (2) and (3) glass are used by SEIKO with the trademark of "HARDLEX" (glass which raised mechanical intensity by special chemical strengthening processing), they are used for standard watches.
On the other hand, sapphire glass (4) is used abundantly for the dress watches and high-class water-resistant watches and also diver's watches, such as CREDOR and Grand SEIKO and also some PROSPEX watches, such as LANDMASTER watches, SCUBAMASTER diver's watches of SEIKO brand, and hardness and theoretical intensity are excellent, there is also a problem of being unable to make as theoretical strength by the mechanism in destruction of the glass with which a cut angle control is important and a micro crack being detected in microscopic examination in case of large and thick glass.
In SEIKO watches, in addition to the above-mentioned general materials, "High- quality HARDLEX" (the high intensity and highly efficient glass strengthened on (3) Borosilicate glass) and original "SAPPHLEX"(the high cost performance combined glass which adhered thin plate of (4) on (2) or (3) glass) are put in practical use, and those are used according to the aim and specification of the watches.
"High- quality HARDLEX" which is the high intensity and the highly efficient article of the glass are used for the PROSPEX watches and ordinary sports watches. Also "SAPPHLEX" glass is used for the sports watches or the sporty watches,
In case of diver's watch which are required so many characteristics totally, such as resistance to pressure, water resistance, shock resistance, wear resistance, heat resistance, and durability etc., we usually use "High- quality HARDLEX" glass having the most excellent cost performance and sometimes use sapphire glass as a glass of some PROSPEX diver's watches.
Ikuo Tokunaga
"
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Existe um Tópico no fórum destinado a esse material.
Abraços,
Thallys Rodrigues
Thauro Relógios