You're comparing two jars. Both list hydroxyapatite. One costs three times the other. Is the word doing the same work in both places? Not necessarily. "Hydroxyapatite" on a label is a category, not a spec, and a few real variables sit behind it. Here's what actually differs, so you can tell a considered ingredient from a buzzword.
Particle form: micro vs. nano
The most consequential difference is particle size. Nano-hydroxyapatite is extremely fine; micro-crystalline is made of larger particles. This isn't a "bigger is better" or "smaller is better" story, and any brand that frames it that way is overreaching. What's true and useful: the modern safety discussion in oral care centers specifically on nano particles, their shape (rod versus needle) and behavior have drawn regulatory attention in Europe, whereas larger micro-crystalline particles sit outside most of that debate. So particle form is worth knowing not because one is magically superior, but because it changes how the ingredient is discussed and regulated. We cover that safety conversation in the hydroxyapatite guide.
Crystallinity and consistency
"Crystallinity" describes how well-ordered the mineral's structure is, and consistency describes how uniform the particles are batch to batch. A well-characterized, consistent material is simply a higher-quality input than a variable one, the same way uniform beans make more reliable coffee. You can't see this from the shelf, which is precisely why it's a place lower-cost products cut corners and premium ones don't.
Purity and source
Purity, how free the material is from unwanted trace content, and source, who makes it and to what grade, round out the picture. None of these show up in the single word on the front of the box. All of them affect what you're actually paying for.
The honest bottom line
Here's the part we won't dress up: a higher percentage or a particular particle form does not let anyone promise your teeth a specific health outcome. The evidence on what topical hydroxyapatite does is promising but still developing, and we keep that honest throughout our hydroxyapatite guide. What quality and disclosure do give you is something you can verify: a known form, a stated amount, a named source. That's the right basis for a premium purchase, transparency you can check, not efficacy you have to take on faith.
Crown's is 15% micro-crystalline hydroxyapatite, sourced from New Zealand, disclosed on the jar. We put the number and the form in plain sight so you can compare us to anyone, and we'd encourage you to ask every other brand for the same three answers before you buy.
Crown Tooth Powder is a cosmetic tooth powder, not a substitute for professional dental care.