I see diamonds showing crystal inclusions a lot nowadays whereas years ago on here most seemed to have feather type inclusions. Was the feeling not that crystal inclusions usually had more strain around them? Is this not a concern anymore?
It all depends on the Clarity, Crystal in nature appear black sometimes and can make the stone look awful however if there is any particular stone you are referring to than more comments are possible.
I was speaking more about the durability of diamonds, where a few years ago people preferred a feather to a crystal in diamonds on this forum. Strain was also being linked then to durability