Apple Watch's Sapphire Crystal Display Evaluated With Diamond Tester

YouTube channel Unbox Therapy has shared a new video that tests the stainless steel Apple Watch with a basic diamond tester to determine if it actually has a sapphire crystal display like many regular mechanical watches. The video also tests the Apple Watch Sport, LG G Watch R, iPhone 6 and a Tissot watch that is verified to have a sapphire crystal display.

applewatchunboxtherapy
The results of the test confirm that the Apple Watch does have a sapphire crystal display as advertised, with the diamond tester recognizing the thermal conductivity of the scratch-resistant material. The verified Tissot watch also displays a reading on the meter, while the Apple Watch Sport, LG G Watch R and iPhone 6 do not yield any results because all three devices have traditional or ion-strengthened glass displays.


Sapphire crystal is a harder and more scratch resistant material than traditional glass, which is why Apple chose it for the more expensive Apple Watch and Apple Watch Edition display and lenses of the heart rate sensor. Apple cut the sapphire crystal with a diamond-encrusted wire to allow for a precise fit and polished it with diamond-covered pellets for a smooth and glossy finish.

"Sapphire is the second-hardest transparent substance after diamond," reads the Apple Watch materials page. "That’s why we chose it to cover the Apple Watch and Apple Watch Edition faces, and to make the lenses of the heart rate sensor. Our sapphire crystal comes from the highest-quality boules. Only the purest, clearest, and strongest sapphire crystal is harvested. To ensure a precise fit for the case, the crystal is cut using a diamond-encrusted wire. To make room for an integrated antenna, a tiny groove is laser-ablated around its perimeter. And to create the smoothest possible finish, the crystal is polished with diamond-covered pellets."

Apple Watch has been put through a variety of tests since it was released last week, giving users an idea of how the wrist-worn device manages based on both normal and unrealistic usage. CNET shared an Apple Watch torture test on Friday that, among other things, involved submerging the watch in hot water and pouring ketchup and maple syrup on it, while another video took the Apple Watch into the shower and swimming pool as part of a waterproof test.

Related Roundup: Apple Watch 11
Buyer's Guide: Apple Watch (Buy Now)

Popular Stories

Foldable iPhone 2023 Feature 1

Apple to Make More Foldable iPhones Than Expected

Tuesday December 9, 2025 9:59 am PST by
Apple has ordered 22 million OLED panels from Samsung Display for the first foldable iPhone, signaling a significantly larger production target than the display industry had previously anticipated, ET News reports. In the now-seemingly deleted report, ET News claimed that Samsung plans to mass-produce 11 million inward-folding OLED displays for Apple next year, as well as 11 million...
iOS 26

15 New Things Your iPhone Can Do in iOS 26.2

Friday December 5, 2025 9:40 am PST by
Apple is about to release iOS 26.2, the second major point update for iPhones since iOS 26 was rolled out in September, and there are at least 15 notable changes and improvements worth checking out. We've rounded them up below. Apple is expected to roll out iOS 26.2 to compatible devices sometime between December 8 and December 16. When the update drops, you can check Apple's servers for the ...
iPhone 14 Pro Dynamic Island

iPhone 18 Pro Leak Adds New Evidence for Under-Display Face ID

Monday December 8, 2025 4:54 am PST by
Apple is actively testing under-screen Face ID for next year's iPhone 18 Pro models using a special "spliced micro-transparent glass" window built into the display, claims a Chinese leaker. According to "Smart Pikachu," a Weibo account that has previously shared accurate supply-chain details on Chinese Android hardware, Apple is testing the special glass as a way to let the TrueDepth...
iOS 26

Apple Seeds Second iOS 26.2 Release Candidate to Developers and Public Beta Testers

Monday December 8, 2025 10:18 am PST by
Apple today seeded the second release candidate version of iOS 26.2 to developers and public beta testers, with the software coming one week after Apple seeded the first RC. The release candidate represents the final version iOS 26.2 that will be provided to the public if no further bugs are found. Registered developers and public beta testers can download the betas from the Settings app on...
Google maps feaure

Google Maps Quietly Added This Long-Overdue Feature for Drivers

Wednesday December 10, 2025 2:52 am PST by
Google Maps on iOS quietly gained a new feature recently that automatically recognizes where you've parked your vehicle and saves the location for you. Announced on LinkedIn by Rio Akasaka, Google Maps' senior product manager, the new feature auto-detects your parked location even if you don't use the parking pin function, saves it for up to 48 hours, and then automatically removes it once...
Johny Srouji

Apple's Chipmaking Chief Johny Srouji Responds to Report About Him Potentially Leaving

Monday December 8, 2025 9:23 am PST by
Apple's chipmaking chief Johny Srouji has reportedly indicated that he plans to continue working for the company for the foreseeable future. "I love my team, and I love my job at Apple, and I don't plan on leaving anytime soon," said Srouji, in a memo obtained by Bloomberg's Mark Gurman. Here is Srouji's full memo, as shared by Bloomberg:I know you've been reading all kind of rumors and...
iPhone 17 Pro Cosmic Orange

10 Reasons to Wait for Next Year's iPhone 18 Pro

Monday December 1, 2025 2:40 am PST by
Apple's iPhone development roadmap runs several years into the future and the company is continually working with suppliers on several successive iPhone models at the same time, which is why we often get rumored features months ahead of launch. The iPhone 18 series is no different, and we already have a good idea of what to expect for the iPhone 18 Pro and iPhone 18 Pro Max. One thing worth...
google pixel 10

Switching Between iPhone and Android Will Get Easier With New Apple and Google Collaboration

Monday December 8, 2025 11:10 am PST by
Apple and Google are teaming up to make it easier for users to switch between iPhone and Android smartphones, according to 9to5Google. There is a new Android Canary build available today that simplifies data transfer between two smartphones, and Apple is going to implement the functionality in an upcoming iOS 26 beta. Apple already has a Move to iOS app for transferring data from an Android...
Apple Fitness Plus expansion hero

Apple Fitness+ Coming to 28 New Regions With Digital Voice Dubbing

Monday December 8, 2025 6:19 am PST by
Apple today announced that Fitness+ is expanding to 28 new markets on December 15 in the service's largest international rollout since launch, accompanied by new language dubbing and a K-Pop music genre. Apple Fitness+ will become available in Chile, Hong Kong, India, the Netherlands, Singapore, Taiwan, and additional regions on December 15, with Japan scheduled to follow early next year....
Johny Srouji

Apple Chip Chief Johny Srouji Could Be Next to Go as Exodus Continues

Sunday December 7, 2025 10:41 am PST by
Apple's senior vice president of hardware technologies Johny Srouji could be the next leading executive to leave the company amid an alarming exodus of leading employees, Bloomberg's Mark Gurman reports. Srouji apparently recently told CEO Tim Cook that he is "seriously considering leaving" in the near future. He intends to join another company if he departs. Srouji leads Apple's chip design ...

Top Rated Comments

OllyW Avatar
139 months ago
I don't think there was ever any doubt about Apple using real sapphire crystal displays. :confused:
Score: 61 Votes (Like | Disagree)
arubinst Avatar
139 months ago
So... was anyone expecting a different outcome?

It's not like Apple is going to sell something else and label it as sapphire :rolleyes:
Score: 28 Votes (Like | Disagree)
Patriot24 Avatar
139 months ago
I think the Unbox Therapy guy is nice and knows his stuff, but my god does he take forever to get to the point in all of his videos. This one in particular could've been 30 seconds.

"Oh look, it really is Sapphire." ROLL CREDITS.
Score: 27 Votes (Like | Disagree)
kdarling Avatar
139 months ago
I don't think there was ever any doubt about Apple using real sapphire crystal displays. :confused:
No kidding! :rolleyes:

How about testing something that we don't know yet. Like:

- What's the battery size in the 42mm????

- How long does a watch go if you put it into Reserve Mode at 100% battery?

- Is there a way to fool the wrist detection and move the watch to another arm?

- Heck, what if you just put a piece of white tape (or a band-aid) under the watch? Does this allow the owner to wear it looser?

- I.e. Is the detection looking for a pulse? And if so, is that only every ten minutes?


- etc
Score: 13 Votes (Like | Disagree)
DavidTheExpert Avatar
139 months ago
I would have gone with the stainless steel model for the sapphire display if only there were more color options. I went with sport because I liked the space gray color better. The space black stainless steel was nice, but it only comes with the link bracelet putting the minimum price at a thousand dollars. Eff that.
Score: 13 Votes (Like | Disagree)
realeric Avatar
139 months ago
Don't feed the troll(=Unbox Therapy).
Score: 11 Votes (Like | Disagree)