There is a lot of hair to dig under, but a journey to the centre of Liam Coltman would reveal a core that is solid, durable and unlikely to melt even if a blowtorch is applied.
It's an assessment that can be made quickly and easily given his reaction to the installation of a new conditioning coach for the Highlanders' forwards during the pre-season. One Bradley Carnegie Thorn decided over the summer he'd like to take responsibility for getting the tight five fit and ready for the season.
Thorn is notorious: the veteran former All Black pushes himself harder than most - which is why at almost 39 he's still in this business. The Franks boys - Owen and Ben - used to have a bit of an exclusive training club with Thorn when they were Crusaders and All Blacks together. Hard-men-only kind of thing, with the rest of the forwards making their excuses.
They all knew the intensity would be extreme and their bodies pushed to, and probably beyond, their limits.
It says plenty for the mindset and ambition of 24-year-old Coltman that he's relished the input of Thorn.
"He is doing the strength and conditioning in the gym for us and he is unreal," says Coltman. "He's actually ... just ... an unreal man. He turns out each week in the footy season and puts everything out there on the field. He's a hard, physical man and a real eye-opener to everyone that sees him play."
This is Coltman's second year in Super rugby and the rudeness of the physical awakening last year is partly why he knows the gym work he's done is critical. Many rookie players, especially forwards, are comfortable with the pace of Super rugby when they step up from the ITM Cup.
It is the relentless intensity of the collisions and contact work that gets to them: the men are bigger, harder, better conditioned and Coltman felt it a bit last year.
He also had his issues with some of the technical craft of being a hooker. "I'm definitely stronger and a lot of that is to do with the gym programme. But my throwing was one thing to work on. I struggled with that but Andrew Hore helped me out.
"It is one of those things ... you just have to front up each week and be physical every game [or] other teams will take advantage of that.
"You get punished as soon as you make the mistake.
"The ITM Cup you can get away with it a little bit."
He mentions Hore, whose absence from the Highlanders is another big difference. Coltman's path is clear to establish himself as the No1 hooker in the franchise. He's dabbled a bit in the past as a prop, switching between the tight-head and middle of the scrum during ITM Cup campaigns. But not now. He wants to specialise at hooker, improve his performance in the core roles and continue to contribute in general play with his abrasive ball-carrying and tackling.
He hasn't hit upon those goals randomly: that's pretty much what he was told by the All Black selectors after he spent a week with the national team last year.
With Hore retired and Keven Mealamu now 34, the All Blacks need a younger man in the mix. Coltman may well be that man if he can deliver with the Highlanders. He has the size, the character and the work ethic.
He now needs to combine all of those into consistent performances.