Platinum is the king of precious metals, and for good reason. It almost only has advantages, with very minimal downsides.

Durability is unmatched. Even when scratched, no metal will be removed. In fact it will be only be moved. That means that unlike gold for example, the metal mass will remain the same even after decades. It is the definition of timelessness.
Its higher density and hardness also mean it will be impervious to external hazards, resisting abrasion and not being damaged by acids.

Platinum has a natural white hue, and it will not tarnish over time. That means its shine or aspect will remain the same. It is often seen as the most noble of metals.


Finally, it is to note that platinum is perfectly hypoallergenic. If you have sensitive skin, you won't need to think twice before picking this metal.

And because we spoke downsides, we wanted to mention the heavier density of platinum, which means a piece of platinum jewelry will be heavier than gold or titanium, for instance.  Besides, being softer than gold, titanium of tantalum, platinum is more easily scratched.

Often referred to as 950 platinum, that means the alloy is composed of 95% platinum, and 5% of another metal, depending on the desired use. 

That 5% will modify the behavior of the platinum alloy, in the objective of reinforcing the platinum's solidity and durability.
For instance, a 95%platinum/5%copper alloy will be slightly softer 
The differences are very marginal, but we felt they were important to mention in keeping with our vision of looking for the most durable.