# Gemetrix vs Diamond Tester

The clearest difference is review sentiment: Gemetrix at 50% against Diamond Tester's 0%. Gemetrix also leads on in-app purchases (none vs 2) and iOS requirement (10.3 vs 17.6). Diamond Tester's advantage is rating (4.5 vs 2.2) and ratings volume (65 vs 5). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Diamond Tester sells 2 in-app purchases, starting at $7.99 per 7 days. Gemetrix asks for nothing beyond the download.

Diamond Tester holds the better App Store score, 4.5 against 2.2. That said, the two scores are not equally well evidenced: Diamond Tester has 65 ratings behind it against 5, so its average is the more settled of the two. Written reviews complicate that: 50% of Gemetrix's written reviews are positive against 0% of Diamond Tester's, so the app with the better star average is not the one people write more warmly about.

Gemetrix ships an update monthly, Diamond Tester fortnightly. The most recent releases landed on November 2, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | Gemetrix | Diamond Tester |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [2.2 (5 ratings)](https://appshunter.io/ios/app/gemetrix/id1363103077/reviews) | **[4.5 (65 ratings)](https://appshunter.io/ios/app/diamond-tester/id6754944343/reviews)** |
| Number of ratings | 5 | **65** |
| Positive reviews | **50.0% of reviews** | 0.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Monthly | **Fortnightly** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 18 MB | 12 MB |
| Requires iOS | **10.3** | 17.6 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [John Chapman](https://appshunter.io/developer/1363103076) | [Nicolas Gustavo Melian](https://appshunter.io/developer/1777868675) |

## What reviewers say

### Gemetrix

[App page](https://appshunter.io/ios/app/gemetrix/id1363103077)

Control your smartphone camera's exposure, ISO, color temperature, and focus for both short-wave and long-wave UV illuminations. Compare captured images side-by-side or with a slider, and save them with clear labeling.

**Highlights:** UV illumination control (SWUV & LWUV), Adjustable exposure, ISO, color temperature, focus, Side-by-side image comparison, Image slider comparison, Save labeled images

**Features:** macOS Compatibility

**In-app purchases:** none


### Diamond Tester

[App page](https://appshunter.io/ios/app/diamond-tester/id6754944343)

Identify real diamonds, gems, and crystals with a photo. Get information on authenticity and estimated value. Organize your findings in a personal collection.

**Highlights:** Photo-based diamond identification, Authenticity verification, Estimated diamond value, Gem and crystal analysis, Personal collection organizer

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weekly Plan | $7.99 | per 7 days |
| Yearly Plan | $24.99 | per year |


## Frequently asked questions

### Is Gemetrix free?

Gemetrix is free to download, with no in-app purchases.

### Is Diamond Tester free?

Diamond Tester is free to download, with in-app purchases available.

### Which has better reviews, Gemetrix or Diamond Tester?

Diamond Tester is rated higher. Gemetrix averages 2.2 out of 5 from 5 ratings, while Diamond Tester averages 4.5 from 65 ratings.

### Do Gemetrix or Diamond Tester have ads?

Neither Gemetrix nor Diamond Tester shows ads.

### Which is updated more often, Gemetrix or Diamond Tester?

Gemetrix ships an update monthly, and Diamond Tester fortnightly. Most recently, Gemetrix was updated on November 2, 2026 and Diamond Tester on October 31, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*