# Rock Identifier Crystal ID vs M

The clearest difference is in-app purchases: M at none against Rock Identifier Crystal ID's 2. M also leads on iOS requirement (15.6 vs 17.0). On price, ads and device support there is nothing between them.

Both are free to download. Rock Identifier Crystal ID sells 2 in-app purchases, starting at $7.99 per month. M asks for nothing beyond the download.

## The numbers

| Metric | Rock Identifier Crystal ID | M |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Weekly | — |
| Size | 76 MB | 42 MB |
| Requires iOS | 17.0 | **15.6** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Omer Faruk Bozbulut](https://appshunter.io/developer/1700207236) | [Marat Shaimov](https://appshunter.io/developer/1531466745) |

## What reviewers say

### Rock Identifier Crystal ID

[App page](https://appshunter.io/ios/app/rock-identifier-crystal-id/id6757540795)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Rock Identifier Premium (monthly) | $7.99 | per month |
| Rock Identifier Premium (annual) | $39.99 | per year |


### M

[App page](https://appshunter.io/ios/app/m-school/id6815974476)

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

**In-app purchases:** none


## Frequently asked questions

### Is Rock Identifier Crystal ID free?

Rock Identifier Crystal ID is free to download, with in-app purchases available.

### Is M free?

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

### Do Rock Identifier Crystal ID or M have ads?

Neither Rock Identifier Crystal ID nor M shows ads.

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