Help Identifying Saudi Guinea

Interesting. I find it strange that they would write 22 in "regular" numerals while the rest of the coin is Arabic.
Notable, the coin specs are 22mm diameter and it is 22k gold. Maybe a clue?
Lastly, you say that you got this from a Saudi Royal. Could it be that these were made special for them? Seems possible.

This is not a "genuine" Saudi guinea, but a jeweller's imitation. Middle eastern gold dealers like to trade bullion in coin form, and will turn their surplus gold into "coins" in order to do so. It is still made of 22k gold, hence the "22" marking. In Dubai, and probably in other Gulf states, making imitation (counterfeit, from our point of view) gold coins is perfectly legal, so long as the jeweller clearly marks what the actual gold fineness is. You can find "British sovereigns" with the "22" (or more commonly, "21") on them, such as the example in this thread.

Less reputable gold dealers make their profits off the unwary buyer by either making their coins slightly lower fineness than the genuine coins (eg. 21k instead of 22k) or making them full fineness but slightly lighter. If a tourist then pays full price for a debased or lightweight coin, well, the seller hasn't broken the law, it's the customer's fault for not doing due diligence.

Thanks Sap,

Yes they are very heavy! So HRH must have had them made to give as gifts.

Thanks for the help!