Mount Ijen is one of the most visited tourist destinations in East Java, other than Mount Bromo. Compared to the neighboring Mount Bromo, Mount Ijen is indeed less famous. However, the beauty of Mount Ijen is not something to be skipped over and deserves some more good publications.
At the Top of the Mountain
Mount Ijen is closer to Bali than to Surabaya, the Capital of East Java. It is located in Banyuwangi regency and about one hour drive from Banyuwangi City. If you visit Bali, you can opt in for an optional tour to Mount Ijen through any tour operators you can find in Bali. It's pretty easy to find a tour operator to go to Mount Ijen from Bali.
Carved Sulphur
In order to go to Mount Ijen, you will have to go on an approximately one hour drive from Banyuwangi City to Paltuding (by any car, since the roads are paved well anyway). Paltuding, the foot of the mountain, is the start point of the hiking trip to the top of the mountain. You can also go to Paltuding from another city, Bondowoso, if you come from another direction (from Surabaya). However, the roads from Bondowoso to Paltuding is said to be less well paved (I haven't confirmed it yet since I didn't go through this way).
Above the Clouds
Once you arrive at Paltuding, you would usually find a lot of locals (usually also sulphur miners) who would offer you a guided hiking trip up to the top of the mountain. It usually costs around IDR 100.000 - IDR 300.000 for the guide fee. But, you can always opt in to go by yourself without a guide.
The Sulphur Miner Weighing His Mine
The hiking trek is in pretty good condition now, so you don't have to worry about the safety too much. The trek is pretty wide consistently, about 4 meters most of the way.
The Bluefire
The most special thing about Mount Ijen is that you can see the bluefire inside the crater. It is said to be one of the only two places where you can see the amazing bluefire in the world. However, in order to see the bluefire, you must be inside the crate in the middle of the night, at around 2-4 am. So, you might need to start your hiking trip at about midnight, reach the mountain top at 2 am, and climb down into the crater for about half an hour to 45 minutes.
Bluefire at Mount Ijen is something that you wouldn't wanna miss and it is a place you would want to see before you die.