For the flesh to stone spell, the process of becoming petrified goes through this sequence: first, you become restrained if you fail a CON save, and must make additional CON saves until you succeed three or fail three, similar to how death saves work. If you fail three before you succeed three, you become petrified.
The flesh to stone spell is a concentration spell, which says (PHB, p. 243):
If you maintain your concentration on this spell for the entire possible duration [1 minute], the creature is turned to stone until the effect is removed.
From this, I have a few closely related questions with regards to how flesh to stone interacts with antimagic field (I decided to split this question up into two sets, since otherwise all 5 questions together made this post too broad; the other set of questions is here):
- If a creature has been petrified by flesh to stone and the caster has concentrated for a full minute on the spell, does antimagic field have any effect on their petrified condition?
- If a creature has been petrified by flesh to stone but the caster has not yet concentrated for a full minute on the spell, does antimagic field have any effect on their petrified condition?
- If a creature has failed their initial save against flesh to stone but they are yet to make their three-of-a-kind saving throws, does antimagic field allow them to auto-succeed the saves and no longer be restrained/turning to stone?