“Know Your Jeweler” has been a slogan since at least the early 1920s, and “Know Your Jeweler if You Don’t Know Diamonds” has been cited in print since at least 1927. The saying means that making a purchase can be confusing, so it’s always wise to buy from someone who is reputable and who inspires trust.
“If You Don’t Know Jewelry, Know Your Jeweler” was the title in a chapter of a 2010 book about investor Warren Buffett, showing that the saying has been applied to other businesses besides jewelry. “If you don’t know coins, know your dealer” is a popular related saying.
16 December 1927, Monessen (PA) Daily Independent, pg. 16 ad:
Know Your Jeweler if You Don’t Know Diamonds
(Brown Jewelry and Ladies Wear—ed.)
14 October 1928, Omaha (NE) World-Herald, sec. E, pg. 8, col. 5 ad:
Something to think about: If you don’t know diamonds, know your jeweler—and I can certainly recommend C. B. Brown’s without the slightest qualm.
14 October 1928, Omaha (NE) World-Herald, sec. E, pg.11, col. 1 ad:
Know Your Jeweler—
If You Don’t Know Diamonds
(Brodegaard Bros. Co.—ed.)
12 December 1937, Springfield (MA) Republicans, pg.4C, col. 1:
IF YOU DON’T KNOW JEWELRY…
KNOW YOUR JEWELER
(Landen & Son Diamonds—ed.)
30 March 1946, Rockford (IL) Register-Republic, pg. 10, col. 1 ad:
Know Your Jeweler
If You Don’t
(Carl E. Lindquist—ed.)
30 November 1949, Seattle (WA) Daily Times, pg. 12, col. 6 ad:
The Northwest’s best diamond buy…if you don’t know DIAMONDS, know your JEWELER.
(Harry Druxman, Gemologist—ed.)
The Catholic Digest
A Washington jewelry store quite reasonably advertises, “If you don’t know diamonds, know your jeweler!”
The old adage, “If you don’t know diamonds, know your jeweler,” most certainly applies when buyers know very little about pianos other than that they have 88 keys.
22 June 1956, Christian Science Monitor, “Gem Selection and Cutting Described by Jeweler"by Ellen K. Rainey, pg.12:
The Sariori slogan is, you know, “If you don’t know jewelry, know your jeweler.”
13 October 1960, Hartford (CT) Courant, pg. 20 ad:
If You Don’t Know Diamonds, Know Your Jeweler
Google News Archive
14 November 1960, Spokane (WA) Daily Chronicle, “Love of Beauty Leads to Career,” pg. 14, cols. 3-4:
His mother’s love of beautiful things led Albert J. Sariori into a 62-year career in the jewelry business.
Sariori, whose jewelry store and jewelry manufacturing shop are at N10 Wall, will note his 62d anniversary in the business in January.
The slogan of Sariori’s jewelry business has for years been “If you don’t know jewelry, know your jeweler.“It is a slogan which has attracted much attention and several years ago it led to Sariori’s being featured in a two-article series in the Christian Science Monitor.
Google News Archive
5 February 1969, Press-Courier (Oxnard, CA), “Don’t Know Gems? Know Jeweler” by Ann Landers, pg. 23, col. 5:
So, 1 repeat, if you don’t know your gems, know your jeweler.
Protect Your Estate:
Definitive Strategies for Estate and Wealth Planning
By Robert A. Esperti and Renno L. Peterson
New York, NY: McGraw-Hill
Our advice is, “If you do not know jewels, know your jeweler.” You should take the time to interview and select an insurance professional who is knowledgeable. You should select an insurance professional you like and one who will work comfortably with your other estate planning advisers.
When the Man in Your Life Can’t Commit
By David Hawkins
Eugene, OR: Harvest House Publishers
I grew up hearing my father repeat an old proverb: If you can’t know your jewels, know your jeweler. If you can’t be sure of what your man is selling you, be sure you know his heart and his character.
Buffett Beyond Value:
Why Warren Buffett Looks to Growth and Management When Investing
By Prem Jain
Hoboken, NJ: John Wiley & Sons
If You Don’t Know Jewelry, Know Your Jeweler