I repeat: twelve hours intervals are prone to abuse, according to all that you stated in all the above comments and in the main article. I will show now a situation that is totally legal and it is an abuse.
Until today I receive a 100% upvote daily, no matter at what time I post and no matter the number of articles using the tag (at least one). Right?
Day 1: I will post an article using the tag at, let's say, 6 AM. I will receive my 100% upvote and a Gem. At 6:01 PM I will post anything, not using the tag. So, I will receive a 50% upvote.
Day 2: I will post an article using the tag at 7 PM. I will receive my 100% upvote and a Gem.
Day 3: I will post an article using the tag at 6 AM. I will receive my 100% upvote. At 6:01 PM I will use the Gem and will receive the 50% upvote.
Day 4: Same as Day 2.

Do you remember why you had to change the 23 hours minimal interval for the bot to upvote an account?
Because fixed time intervals are always prone to abuse. That is why Precious votes once a day, no matter at what time the post was published.

I propose, again, what I wrote above:
"The member posts today using the tag and receives the Precious Gem. Today he/she will not receive any other upvote from Precious. Tomorrow he/she will receive his/her due upvote, irrelevant if he/she used or not the tag and will not receive any other upvote tomorrow. And that goes on. You write about precious metals, you receive one Precious Gem (you can only have one PG at any time) and you use it the next time you write a tagless post, never receiving two upvotes on the same day.
Of course, if you do not post for a few days, you have Precious's votes accumulating in value, but this does not affect the idea behind Precious Gems."
@buggedout @welshstacker