Obsidian is a volcanic glass made mostly of silicon dioxide. It has been used by early civilizations as a spear point material and now it is used as a material for scalpels for surgery. Obsidian blade can reach molecular thinness, down to 3 nanometers across. It is the sharpest blade that can be made.
This quality of blade makes for less scar tissue and less inflammation.
Observe the current popularity with Strongman training in modern Strength and Conditioning. Apparently, all the best stuff to workout with is actually big tyres, kegs, stones, rocks, unstable objects, barrels of water, various discarded pieces of heavy metal and heavy vehicles.
The ‘World’s Strongest Man’ contest is a well marketed annual event with lead in qualifiers that pit very large and strong men against each other in a variety of weighted events. They draw large live and television audiences. It is a form of sports entertainment, legitimate competition nonetheless, but not too many steps away from Championship Wrestling in how it is marketed and in whom it is marketed to.
Strongman events dispense with more traditional implements of strength development like barbells and that is fine, it is the leveraging of the popularity of the sport into trying to be a solution to athletic problems which is where somewhat of a problem arises. Barbells have stood the test of time for a few reasons.
Firstly, they are easy to hold onto. This is important because if someone is trying to get strong then actually holding on to and balancing the implement that is providing the resistance should not be the biggest impediment. Grip strength is a well worthwhile area for development for athletes but most athletes need a lot more development of strength of the musculature of the arms, legs and trunk; not a singular focus on grip strength or coordination of specific odd implements.
Secondly, barbells are symmetrical. Balance is not the main issue in lifting them. The well coached lifter is able to perform lifts so that the failure issue comes down to the contractile potential of the prime moving musculature, not the specific coordination in lifting the individual characteristics of the implement itself. Balance is salient in lifting but not the target. A heavy unstable object asks much more of the lifters ability to balance it in order to express his or her strength. A fridge might weigh 90kg; nearly impossible to move due to its size, a 90kg barbell is easy to lift. Some objects have a specific balance requirement so much so that developing ability in lifting the object may not have much transfer over to lifting any other object. It doesn’t take long to look around and realize that there has been a massive over prescription of balance specific exercises.
Thirdly, barbells are incrementally loadable and variable. It is extremely easy to quantify the improvement in a barbell lift because it is relatively easy to measure how much weight is on the bar, how far it moves and how long it takes. Right down to placing fridge magnets on the end, you know that the barbell is heavier and by precisely how much.