Which preposition to use with touchstones

of Occurrences 37%

He was the proof and touchstone of all my cogitations."

for Occurrences 9%

In this controversy, in which Whetstone later took sides with the anti-stage party in his Touchstone for Time (1584), the age-long conflict between the poets and the philosophers was renewed with vigor and acrimony.

by Occurrences 7%

I call him my testthe touchstone by which I try a friend.

to Occurrences 6%

Sympathy!it is the touchstone to every secret, the key to all knowledge, the open sesame of all hearts.

in Occurrences 4%

The Fainalls, etc. Fainall in Congreve's "Way of the World," Mirabel in Farquhar's "Inconstant," Dorimant in Etheredge's "Man of Mode," and Lady Touchstone in Congreve's "Double Dealer.

Which preposition to use with  touchstones