The fire in the flint
Shows not till it be struck. [ William Shakespeare ]

In the coldest flint there is hot fire. [ Proverb ]

That carries anger as the flint bears fire;
Who, much enforced, shows a hasty spark,
And straight is cold again. [ Jul. Caes ]

Scarce can I speak, my choler is so great.
Oh! I could hew up rocks, and fight with flint. [ William Shakespeare ]

The fire in the flint shows not till it's struck. [ Proverb ]

So light a foot will never wear out the everlasting flint. [ William Shakespeare ]

Weariness can snore upon the flint, when restive sloth finds the down pillow hard. [ William Shakespeare ]

As the evening sun faded from a salmon color to a sort of flint gray, I thought back to the salmon I caught that morning, and how gray he was, and how I named him Flint. [ Jack Handey, Deep Thoughts ]

All the means of action, the shapeless masses - the materials - lie everywhere about us. What we need is the celestial fire to change the flint into transparent crystal, bright and clear. That fire is genius! [ Longfellow ]

Greatness is not a teachable nor gainable thing, but the expression of the mind of a God-made man: teach, or preach, or labour as you will, everlasting difference is set between one man's capacity and another's; and this God-given supremacy is the priceless thing, always just as rare in the world at one time as another.... And nearly the best thing that men can generally do is to set themselves, not to the attainment, but the discovery of this: learning to know gold, when we see it, from iron-glance, and diamond from flint-sand, being for most of us a more profitable employment than trying to make diamonds of our own charcoal. [ John Ruskin ]