The Kreknorite Meteor is an uncommon meteor that is extremely devastating to your land if not destroyed quickly. This meteor is rarer than the Frezarite Meteor which is rarer than the Meteorite Meteor. Blazes will occassionally spawn with this meteor. When the meteor is medium or large sized (by default), a portal to the nether will form above the crash site. The portal structure will include some nether brick blocks and some glowstone on its ceiling.
When the kreknorite ore in the crash site cools, it turns into obsidian which is the reason why this meteor can be extremely devastating to your environment.
Kreknorite ore is your primary resource to be gathered at the crash site. The Kreknorite Chips can be used to craft a very strong set of armor that grants you complete immunity to fire/lava when wearing the complete set. You can also craft a decently strong sword with Fire Aspect.
The crash site could also be used to gather glowstone and nether brick without going to the nether. It also allows you to travel to the nether without getting a diamond pick for obsidian gathering.