"a spark of insight" is a correct and commonly used phrase in written English.
It is often used to describe a sudden burst of understanding or a moment of clarity. Example: After struggling with the problem for hours, she suddenly had a spark of insight and was able to solve it.
In purportedly morally mature mystical people who have developed this capacity through daily contemplation or meditation combined with selfless service to others, critical conscience can be aided by a "spark" of intuitive insight or revelation (called marifa in Islamic Sufi philosophy and synderesis in medieval Christian scholastic moral philosophy).
When Clark suggests what we should do for impoverished coffee growers, he does so with the same spark of insight about market freedoms that must have once flashed upon the young Adam Smith: "Demand the best-tasting coffee you can get".
His spark of insight to start Wealthfront came after years of conversations with business school students, many working technology industry, asking him how to manage their compensation plans and personal investments.
A spark of vitality went out.
Most simply explained, it begins with a thought what some might call a "spark" of insight that gets translated onto a fixed medium which comes to occupy its final form.
As it turned out, the intensity of his inner struggle galvanized his genius and threw off sparks of insight and prophecy.
Most people, Granoetter discovered, find new jobs, or for that matter new information or new sparks of insight not from those we are close to, but rather from those we are acquainted with — those who are currently leading different lives than we are.
These workers are actually pushed to take regular breaks, as time away from a problem can help spark a moment of insight.
I even feel the spark of an insight: There is time, and energy, for everything that matters.
