Cognism Diamond Data: What 'Phone-Verified' Covers, and What to Check Yourself

A Diamond badge in Cognism tells you a mobile number was confirmed by a call. It doesn't tell you the email works, or that the person is still in that job today. Cognism's own page defines phone-verified as a process that calls the number and checks the right person answers. That's a strong check on the phone number on the day it was made. For email, and for everything after that day, you still check yourself.

Sources, read 2 November 2026: Cognism's Diamond Data page (phone-verified definition, email verification step, 16 DNC lists) and Cognism's help centre article Diamond Data and Diamonds-on-Demand (re-verification about every 18 months, on-demand verification).

What Cognism says each check is

Check	How Cognism describes it	What it tells you
Phone-verified (Diamond)	"A routine process in place that calls the numbers and confirms that it is the right person who picks up the phone"	The mobile reached the right person when called
Email verification	Its AI "scans metadata to verify email addresses"	A model's judgment on the address, not a phone call
DNC screening	Data "cross-checked against 16 DNC lists globally"	Numbers on those lists are flagged
Re-verification	Diamond contacts re-verified approximately every 18 months (help centre)	A Diamond can be up to that old

The connect-rate comparisons on the same page are Cognism's own study figures. Useful context, but measure your own.

What the badge doesn't cover

• The email. The phone call checks the number. Whether the mailbox exists today is a separate question.
• Job changes since the call. A mobile number usually follows the person; their work email doesn't. Someone verified a year ago who has moved company may still answer the Diamond mobile while their work address now bounces. See the email verified as valid but the person left.
• Your calling obligations. DNC screening against Cognism's lists doesn't replace your own consent rules, calling hours and internal do-not-call list. The TCPA calling hours checker covers the US timing rule.

What to check before a campaign

1. Download the revealed contacts and keep Cognism's email and phone status columns. The Cognism export to email list tool separates verified, unverified and role addresses in your browser.
2. Verify the emails on the day you load them into a sequencer, on the verify page. Sort invalid out, send to valid first.
3. Format-check the phone column. Exports pass through spreadsheets that strip plus signs and leading zeros. The phone number validator checks format and number type against the numbering plan.
4. Track results by source. Bounce and connect rates for Diamond versus non-Diamond contacts tell you what the badge is worth on your market.

The general Cognism export routine (sorting by email status, off-domain addresses, contacts per company, UK and EU rules) is in cleaning a Cognism export.

Honest limits on the email check

Many B2B domains are catch-alls that accept every address, so a single mailbox can't be confirmed, and Microsoft-hosted mailboxes, including consumer ones (outlook.com, hotmail.com), don't answer single-mailbox checks reliably. Those come back risky or unknown. For a Diamond contact with a risky email, the phone is the safer first touch.

Where SimpleVerifier fits

Verify the email column of a Cognism export on the verify page; the first 100 checks are free with a Google sign-in. Pro is $39 a month with the first 100,000 checks a month at full speed, then slower, never cut off, and includes phone format checks. See pricing.