As far as I am aware, there are no quotes relating specifically to the indestructibility of the Elder Wand. However, we have good canon reason to believe it indestructible, or at least very durable.
Consider the other Hallows.
The Invisibility Cloak appears to be resistant to wear, and Ron suggests that spells normally can destroy invisibility cloaks:
“But all the stuff he said about the other cloaks, and they’re not exactly ten a Knut, you know, is true! It’s never occurred to me before, but I’ve heard stuff about charms wearing off cloaks when they get old, or them being ripped apart by spells so they’ve got holes in them. Harry’s was owned by his dad, so it’s not exactly new, is it, but it’s just. . . perfect!”
—Harry Potter and the Deathly Hallows
It seems safe to say that the Cloak of Invisibility has been hit by some spells over the course of its lifetime, yet it survived entirely intact until Harry's day.
Similarly, the magic of the Resurrection Stone proved highly resistant to damage. Dumbledore smashed it with the Sword of Gryffindor, which was impregnated with Basilisk venom, cracking the ring. Basilisk venom is a substance so magically destructive that even the protection and repair spells on a Horcrux do not affect it. Yet the power of the ring survived this highly destructive substance, even after the Horcrux within was destroyed.
The black stone with its jagged crack running down the center sat in the two halves of the Snitch. The Resurrection Stone had cracked down the vertical line representing the Elder Wand. The triangle and circle representing the Cloak and the stone were still discernible.
—Harry Potter and the Deathly Hallows
Given the durability of the other two Hallows, it seems almost certain that the Elder Wand possesses a similar degree of protection; which is to say, even more protection than a Horcrux. Is it indestructible? Perhaps not. But certainly it would take far more than snapping it in half to destroy it.
