You should not be putting out your ideas in a public forum like this. There are many patent attorneys from Avvo who can help you with how to patent designs. Please contact a patent attorney and discuss in confidence.
The foregoing does not constitute legal advice. No attorney-client relationship exists between me and you. Please consult a qualified attorney before making any significant decision.
You should apply for a design patent for each unique ornamental design you have. Design patents are relatively easy to prepare and provide protection for 14 years from the date of issuance of the patent. A patent attorney familiar with design patents can help you prepare and prosecute the applications to grant of the patents.
You have received good advice...including being careful about disclosure in a public forum. There is new case law relating to claim scope and enforceability of design patents. You need proper counsel before proceeding. Many Registered Patent Attorneys, such as myself, give free consultations. If you do not contact me, at least please make sure you are only dealing with a Registered Patent Attorney.
I would take an entirely different approach than my colleagues. I think you want to rely on copyright protection for this rather than get a design patent. So, I think you need to see an experienced IP attorney and ask about copyright protection.
An ornamental rock design is likely a non-functional work of art, and if so already protected by copyright the moment you create it. That protection lasts nearly a century (your lifetime plus 70 years) and is automatic without cost or formality. Per 17 USC 102(a)
"Copyright protection subsists, in accordance with this title, in original works of authorship fixed in any tangible medium of expression, now known or later developed, from which they can be perceived, reproduced, or otherwise communicated, . . . Works of authorship include the following categories:
. . .
(5) pictorial, graphic, and sculptural works; . . ."
Your attorney can register such protection at the US Copyright Office and can likely do it for all your different rock designs in one copyright application for one $35 filing fee and a few hundred dollars of attorney fees in processing of the application. That will save you thousands of dollars and give you about 7 times longer period of protection.
In fact, if you file for design patents on these, you will forfeit your copyright protection at the end of 14 years when the design patent expires, thus cutting your effective period of copyright protection that you already have by more than 80%. That is, getting a design patent is likely to HURT you.
Seek out an attorney that looks past what you ask and finds what you need and what is most effective for you. Try to not destroy the protection you have in order to get expensive protection you may not need or even want.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.
One final tidbit for you to think about; if you have found a novel manner of making your boxes, that had never been done before and it resulted in a better box, then you could have the basics of a utility patent, and as such you could be the only one who could make boxes with rocks in your manner (people could do it any method that was not your patented method.) This is a utility patent, and it lasts 20 years.
A design patent would cover just that, the design, but only that particular design. Someone else could still ake boxes with rocks on them in a different design. 14 years.
A copyright would prohibit anyone from "copying" your creation. (And as poiinted out is much less expensive.) The question is whether this extends to having different rocks, different wood, different designs? Probably not, but it does last 75 years past the death of the artist/author.
A trademark would protect your brand and the reputation of your skill as an artisan (and last as long as the brand continues to be used by you, your heirs, assignees) from people trying to pass off their product as an original "Box o Rox" guy. This assumes you build a reputation and a distinct immediately recognizable mark on your goods that distinguishes to buyers that this box was made by "Box o Rox" guy. (This is why many native american artists have a distinct mark on their work, which identifies their work from others.)
If you incorporate some identifiable mark on every box you made, then you would be trademarking your product and only you could use that mark (for example, mabe you have a specific type, size, shape rock with a distinct mark on it, on every box). This would not prevent someone from making boxes with rocks on them (neither will patent or copyright), but would protect you from others copying your particular style (to the extent your "style" becomes famous or well known.)
You have many options. Good luck.
My disclaimer is simply that Avvo already has an adequate disclaimer.
Short Answer: Design patents cover ornamental, decorative aspects of objects (including virtual objects such as computer icons). Compared to utility patents, design patents are much easier and less expensive to obtain and take a much shorter time to process at the patent office. However, the scope of design patents is much narrower. Therefore your best bet is to try to obtain several design patents on alternative arrangements of your design to get broader coverage.
Your work may also qualify for copyright protection, which has the benefit of entitling the owner to automatic damages in the event of a dispute. Good Luck.