For years, the phenomenally popular world-building game Minecraft has quietly been making inroads into schools — teachers have been using it informally to teach nearly every subject, mostly through shared, often homemade lessons.

The game’s owner, the software giant Microsoft, has encouraged teachers to use the game. On Tuesday, it took one more step toward formally acknowledging Minecraft’s educational possibilities: it said it had acquiredMinecraftEdu, an education-oriented version created by teachers and explicitly for use in classrooms.

Microsoft did not disclose the terms of the deal, but said it was not acquiring TeacherGaming, the startup that created the “edu” version of the software.

Originally a Swedish import, Minecraft became a Microsoft property more than a year ago, when the Redmond, Wash., company bought it for $2.5 billion.

It’s hard to overstate exactly how huge Minecraft is, especially among young players. It boasts more than 100 million registered players in 238 countries and is among the the best-selling PC games of all time. More than 160 million people have watched more than 5 billion hours of Minecraft video content on YouTube, Microsoft says, with online maps so large they contain up to 921.6 quadrillion individual blocks.

Microsoft says the educational version is already being played in more than 7,000 classrooms in more than 40 countries, but not without issues, officials said.

For one thing, teachers sometimes have difficulty getting it purchased and configured in their classrooms, said Matt Booty, a Microsoft vice president and part of the Minecraft Education team. Until recently, they were required to buy the software through a purchase order made out to its creator, the Swedish game studio Mojang.

Making the educational version of the game a Microsoft purchase “makes it easier and more streamlined for teachers and educators to get Minecraft in the classroom,” Booty said. “If a school can piggyback on its existing arrangement with Microsoft for other software that we already make available to schools, it just makes it easier.”

He also said TeacherGaming had done a lot to create “communities of teachers” who collaborate and share student work.

As for branding a phenomenally popular game “educational,” Booty said he and others were proceeding cautiously, calling Minecraft “a game that has application in education,” not an educational game.

“Our belief is that it stays true to its origins as a game and we make sure that it can be used broadly in educational settings, rather than trying to change something about the game itself,” he said.

Kids “are great at sort of seeing through to the truth of things,” Booty said. “They’re probably better than anybody at seeing through labels.” But they’ll soon see that the Minecraft they’re using in the classroom “is the same as the Minecraft that they play elsewhere, and that it perhaps has just some additional things added — we’re not taking things out. I think that they’ll be at ease to understand that it hasn’t been compromised.”

Microsoft will offer a free trial this summer and expects the new version to cost about $5 per student per year.

The company said it would explicitly separate students’ school accounts from their private accounts, mostly for privacy reasons. But Booty said the software would allow students to take assignments home and share them with parents and friends. It would also create a “portfolio” of work that resides in a personal folder.

Lucas Gillispie, a North Carolina educator who has initiated Minecraft programs in more than 23 schools in two North Carolina districts, said he was “really excited” about the acquisition. “Since I’ve been working with teachers and districts with games and learning, no other tool has come close to Minecraft’s ability to unleash kids’ creativity both in and out of the classroom.”

Gillispie, the director of Academic and Digital Learning for Surry County, N.C., schools, added, “I’ve seen amazing things from both students and teachers in Minecraft. I hope this opens up possibilities for even more students.”

Gillispie also said teachers, as well as gamers, probably shouldn’t worry that Microsoft is ruining a good thing. “I’ve been to a couple of events that Minecraft has hosted … and I get a strong vibe that they are paying close attention to the education community and what we value in the game.”

Follow Greg Toppo on Twitter: @gtoppo