1. Mount Rinjani, also known as Gunung Rinjani, is an active volcano located on the island of Lombok in Indonesia. It is the second-highest volcano in Indonesia, standing at an impressive height of 3,726 meters (12,224 feet) above sea level. The volcano is a popular destination for trekkers and hikers due to its challenging terrain and breathtaking views of the surrounding landscape.

One of the highlights of a trek up Mount Rinjani is the stunning crater lake, known as Segara Anak, which is located near the summit. The lake is considered sacred by the local Sasak people and is believed to be a spiritual place. The volcano is also home to a large population of wildlife, including monkeys, deer, and various bird species.

2. The trek up Mount Rinjani typically takes around 2-4 days, depending on the route chosen and the fitness level of the hiker. The best time to climb the volcano is during the dry season, which typically runs from April to December. It is recommended to hire a guide or join a tour group for the trek, as the terrain can be challenging and proper preparation is essential.

Unfortunately, there is no specific working time or phone number for Mount Rinjani itself, as it is a natural site. However, there are tour operators and guides who can help arrange treks up the mountain and provide information on the best times to visit.

3. Ticket information for climbing Mount Rinjani can vary depending on the route and services included in the trek. It is essential to book a trek with a reputable tour operator or guide, as they will arrange permits, camping equipment, meals, and transportation to the starting point of the trek. Prices can range from a few hundred dollars to over a thousand dollars, depending on the length and level of comfort desired for the trek. Transportation to Lombok can be arranged through flights to Lombok International Airport or by boat from nearby islands.