Written by Acorn Sales Company, manufacturing stamps and seals since 1964 · Reviewed by Holly R, VP of Sales and Marketing at Acorn Sales, against the Board for Professional Engineers, Land Surveyors, and Geologists and Cal. Bus. & Prof. Code §§ 7835, 7852 on 21 September 2026 · Updated 21 September 2026
A California geologist seal is at least one and one half inches in diameter, reading Professional Geologist within the top border and State of California within the bottom border, with your name as it appears on your certificate and your license number. Section 3008(a) of title 16 of the California Code of Regulations sets all of that, and Business and Professions Code section 7852(a) requires each licensed geologist to obtain the seal on licensure. Section 7835 supplies the duty: geologic plans, specifications, reports or documents “shall be signed by the professional geologist or licensed certified specialty geologist and stamped with his or her seal, both of which shall indicate his or her responsibility for them.”
California is the only state with a document its geologists may not seal. Section 3008(d) forbids the seal on a Real Estate Transfer Disclosure Statement required by Civil Code section 1102.6, and in the same breath requires it on “any geologic or geophysical report or opinion” within your scope that is attached separately as a substituted disclosure under that same statute. Seal the attached report, never the disclosure form.
Specialty certification means a second stamp, not an extra line. Section 3008(b) prescribes a separate seal reading Certified Engineering Geologist or Certified Hydrogeologist with the certification number in the center, and section 3008(c) a third for the Professional Geophysicist. There is no combined California geology seal, so a licensee holding a general license and a specialty certification buys two devices.
California geologist seal requirements at a glance
| Requirement | California rule | Source |
|---|---|---|
| Seal required | Yes | Cal. Bus. & Prof. Code §§ 7835, 7852 |
| Required elements | Professional Geologist within the top border, State of California within the bottom border, Your name as it appears on your certificate and Your license or authority number | Cal. Code Regs. tit. 16, § 3008(a) |
| Size and shape | Not less than one and one half inches in diameter. | Cal. Code Regs. tit. 16, § 3008(a), (b), (c) |
| Device allowed | All three families are legal. | Cal. Code Regs. tit. 16, § 3008(a), (f) |
| Signature and date | Seal, signature and date, with the date placed by rule. | Cal. Code Regs. tit. 16, § 3008(f), (g), (h), (i) |
| What must be sealed | Section 3008(h)(1) reaches “All professional geological plans, specifications, reports, or documents,” which must be signed and sealed so that all work can be clearly attributed to the licensee or licensees in responsible charge. | Cal. Bus. & Prof. Code § 7835 |
| Electronic seal | Permitted, with no named technology. | Cal. Code Regs. tit. 16, § 3008(f) |
| Renewal and lapse | The seal carries the certificate number and no expiration date, so renewal never obsoletes the device and the number does not change. | Cal. Bus. & Prof. Code § 7852 |
| Firm requirements | Not applicable. | Cal. Code Regs. tit. 16, § 3008(a)(3) |
| Regulator | The Board for Professional Engineers, Land Surveyors, and Geologists | Geologist and Geophysicist Act, Cal. Bus. & Prof. Code §§ 7800 to 7887, principally §§ 7835 and 7852 |
Is a seal required in California?
Business and Professions Code section 7852(a) creates the seal: “Each geologist licensed under this chapter shall, upon licensure, obtain a seal of the design authorized by the board bearing the licensee’s name, number of his or her certificate, and the legend ‘professional geologist.’” Subdivision (b) does the same for a certified specialty geologist, with the specialty legend in place of the general one. Section 7835 supplies the duty: all geologic plans, specifications, reports or documents “shall be signed by the professional geologist or licensed certified specialty geologist and stamped with his or her seal, both of which shall indicate his or her responsibility for them.” The design, the diameter and the signing mechanics are in California Code of Regulations title 16 section 3008.
What must appear on the seal
- Professional Geologist within the top border
- State of California within the bottom border
- Your name as it appears on your certificate
- Your license or authority number
Specialty certification is a second device, not an extra line. Section 3008(b) gives the certified specialty geologist a separate seal reading either “Certified Engineering Geologist” or “Certified Hydrogeologist” in the top border, with the number of the certification in the center. A professional geophysicist has a third seal under section 3008(c) reading “Professional Geophysicist.” A licensee who holds a general license and a specialty certification buys two stamps rather than one combined stamp, because each subdivision prescribes its own legend and its own number. Section 3008(e) permits an abbreviated given name or initials provided the surname listed with the Board appears on the seal and in the signature. Section 3008(g) prohibits preprinting blank forms with the seal or signature, decals of the seal or signature, and a rubber stamp of the signature.
Size and shape
Not less than one and one half inches in diameter. Section 3008(a) states the floor for the professional geologist seal, and subdivisions (b) and (c) repeat the same figure for the specialty and geophysicist seals. No ceiling is given.
Embosser, rubber stamp or digital
All three families are legal. Section 3008(f): “The seal shall be capable of leaving a permanent ink representation, a permanent impression, or an electronically-generated representation on the documents. The signature may be applied to the documents electronically.” Subdivision (a) also confirms the seal “may be purchased by the licensee from any convenient source.” The safe buy is an inked stamp, because California geology output is largely reports that get copied and attached to filings, and an unfilled embossed impression does not survive a scan.
Signing and dating
Seal, signature and date, with the date placed by rule. Section 3008(i): “Each licensee shall include the date of signing and sealing immediately below or next to the signature and seal.” The signature must be handwritten or a genuine electronic signature; section 3008(g) bans a rubber stamp of the signature. Where two or more licensees are in responsible charge, section 3008(h)(2) requires the signature and seal of each, with a notation describing the work done under each licensee’s responsible charge. Nothing requires the signature to run across the seal.
The one document a California geologist may not seal
Section 3008(d) is unique among the fifty states. It forbids the professional geologist seal and the professional geophysicist seal on a Real Estate Transfer Disclosure Statement under Civil Code section 1102.6, and then in the same breath requires the seal on any geologic or geophysical report or opinion within the licensee’s scope that is attached separately as a substituted disclosure under that same statute. Seal the attached report; never seal the disclosure form itself.
Which documents must be sealed
Section 3008(h)(1) reaches “All professional geological plans, specifications, reports, or documents,” which must be signed and sealed so that all work can be clearly attributed to the licensee or licensees in responsible charge. Section 7835 says the same in the statute. There is one express carve out and it runs the other way from the usual: section 3008(d) provides that the seal “shall not be used on a Real Estate Transfer Disclosure Statement required by Section 1102.6 of the Civil Code,” but that it “shall be used on any geologic or geophysical report or opinion” within the licensee’s scope if that report is attached separately as a substituted disclosure under the same Civil Code section.
Electronic and digital seals
Permitted, with no named technology. Section 3008(f) allows an electronically generated representation of the seal and an electronically applied signature, and stops there. The Geologist and Geophysicist Act and the regulations at title 16 sections 3000 through 3067 name no certificate authority, no hash standard and no file format. Where a California public entity chooses to accept a digital signature, Government Code section 16.5 and the Secretary of State regulations at title 2 sections 22000 through 22005 control that agency’s acceptance, approving public key cryptography and signature dynamics. That is not a Board requirement on the geologist.
Renewal, lapse and retirement
The seal carries the certificate number and no expiration date, so renewal never obsoletes the device and the number does not change. Whether a lapsed, retired, suspended or revoked licensee must surrender or destroy the seal is not addressed: neither section 7852 nor section 3008 says anything about surrender, and the Board’s published regulations relating to geology and geophysics carry no surrender rule. Checked Business and Professions Code sections 7800 through 7887 as published by the Board and title 16 sections 3000 through 3067.
Firm requirements
Not applicable. California issues no geology firm certificate of authorization and no firm number belongs on the seal. Section 3008(a)(3) closes the center of the seal to the licensee’s name and number, and the Board maintains no firm register for geology. Firm identity belongs on the report cover, not in the ring.
What to check before you order
Order an inked stamp at least one and one half inches across. Top band: Professional Geologist. Bottom band: State of California. Center: your name as it appears on your certificate, with your license number. If you also hold a specialty certification, order a second stamp reading Certified Engineering Geologist or Certified Hydrogeologist with that certification number, because the rule prescribes separate devices rather than a combined one. Leave off any expiration date or firm name. Do not order a stamp of your signature, seal decals or preprinted forms bearing your seal; section 3008(g) prohibits all three. The rule states you may buy the seal from any convenient source, and no proof of licensure is required of the supplier.
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Frequently asked questions
Is a geologist seal required in California?
Yes. Business and Professions Code section 7852(a) provides that “Each geologist licensed under this chapter shall, upon licensure, obtain a seal of the design authorized by the board bearing the licensee’s name, number of his or her certificate, and the legend ‘professional geologist.’” Section 7835 then requires all geologic plans, specifications, reports or documents to be signed and stamped. Section 3008(h)(1) repeats the duty in the regulation, so all work can be clearly attributed to the licensee or licensees in responsible charge.
What size is a California geologist seal?
Not less than one and one half inches in diameter, under section 3008(a). Subdivisions (b) and (c) repeat the same figure for the certified specialty geologist and professional geophysicist seals. No ceiling is given, so that figure is a floor and you can go larger where legibility on a report cover calls for it.
What wording goes on a California geologist seal?
Professional Geologist within the top border, State of California within the bottom border, your name as it appears on your certificate, and your license or authority number. Section 3008(e) permits an abbreviated given name or initials provided the surname listed with the Board appears both on the seal and in the signature. No expiration date belongs on the face and no firm name belongs in the ring.
Can I put my specialty certification on the same seal?
No. Section 3008(b) gives the certified specialty geologist its own device reading Certified Engineering Geologist or Certified Hydrogeologist in the top border with the number of the certification in the center, and section 3008(c) gives the professional geophysicist a third reading Professional Geophysicist. Each subdivision prescribes its own legend and its own number, so holding both credentials means owning both stamps.
Rubber stamp, embosser or electronic in California?
All three are legal. Section 3008(f) provides that “The seal shall be capable of leaving a permanent ink representation, a permanent impression, or an electronically-generated representation on the documents. The signature may be applied to the documents electronically.” An inked stamp is the practical choice, because California geology output is largely reports that get copied and attached to filings and an unfilled embossed impression does not survive a scan. Section 3008(a) confirms the seal may be purchased from any convenient source.
Where do the signature and date go?
Section 3008(i) is specific: “Each licensee shall include the date of signing and sealing immediately below or next to the signature and seal.” The signature must be handwritten or a genuine electronic signature, and nothing requires it to run across the seal. Where two or more licensees are in responsible charge, section 3008(h)(2) requires the signature and seal of each, with a notation describing the work done under each licensee’s responsible charge.
What is prohibited on a California geologist seal?
Three products, all named in section 3008(g): preprinting blank forms with the seal or signature, decals of the seal or signature, and a rubber stamp of the signature. A rubber stamp of the seal itself is fine; a rubber stamp of your handwriting is not. That split matches the California engineer and surveyor rule at section 411 rather than the architect rule.
Which document may a California geologist not seal?
A Real Estate Transfer Disclosure Statement required by Civil Code section 1102.6. Section 3008(d) says the seal “shall not be used” on that form, and then says it “shall be used on any geologic or geophysical report or opinion” within the licensee’s scope if that report is attached separately as a substituted disclosure under the same Civil Code section. No other state has this pairing.
Does California set an electronic sealing standard for geologists?
It names no technology. Section 3008(f) allows an electronically generated representation of the seal and an electronically applied signature and stops there, and the Geologist and Geophysicist Act with the regulations at title 16 sections 3000 through 3067 names no certificate authority, no hash standard and no file format. Where a California public entity chooses to accept a digital signature, Government Code section 16.5 and the Secretary of State regulations at title 2 sections 22000 through 22005 control that agency’s acceptance, approving public key cryptography and signature dynamics. That is the agency’s rule, not a Board requirement on you.
Does my seal expire, and must I surrender it?
The seal carries your certificate number and no expiration date, so renewal never obsoletes the device and the number does not change. Whether a lapsed, retired, suspended or revoked licensee must surrender or destroy the seal is not stated anywhere: neither section 7852 nor section 3008 mentions surrender, and the Board’s published geology and geophysics regulations carry no surrender rule.
