Dear Aspirant, there are various colleges and Universities in India for certification courses in Geology. To become a Geologist, You have to have a masters degree in Geology. After getting Masters degree in Geology, you will be technically eligible to work as Geologist.
There are several diploma courses offered by Universities. But obtaining these certificate of diploma course will not fetch you a good job, Moreover a diploma holder cannot be called or write as Geologist. For this you have to study Geology in Bachelor as one subject and have to do Master degree in Geology as Major subject. The reason is obvious, a master degree will let you know more and more compared to a diploma course.
I am writing list of Universities in India offering courses in Geology:
Chaudhary Charan SIngh University, Meerut, UP, Chatrapati Sahuji Maharaj University, Kanpur, UP, Devi Ahilya Vishwavidhlaya, Indore, MP, Kurukshetra University, Kurikshetra, Haryana, Mahrashi Dayanand University, Rohtak, Haryana, Vikram University, Ujjain, MP., Univesity of Delhi, HNB Garhwal University, Srinagar, Uttrakhand, Kumaun University, Nainital, Uttrakhand, Pandit Ravi Shankar University, Raipur, Chattisgarh, Dr. Hari Singh Gaur Univesrity, Sagar, MP, University of Kshmir, Shrinagar, Barkhatullah Vishvavidhalaya, Bhopal, Aligarh Muslim University, Aligarh, Up, Banaras Hindu Vishwavidhlaya, Bnaras, UP,
In south India,:
Sri Venkateshwara Univesity, Tirupati, Osmania University, Hyderabad, Univesrity of Mysore, Mysor, Karnataka, Madurai Kamraj Univesity, Madurai, Tamilnadu, Gulbarga University Gulbarga, Karnataka, Kaktiya University, Warangal, Andhra Pradesh, Bangalore University, Bangalore, Karnataka.

Eastern Universities:
Uttakal University, Bhuvnashwar, Patna Univesrity, Patna, Bihar.

Certificate and diploma courses in Geology are also offered by some these universities, but in my opinion you should go for a degree course from a reputed university. Now there is another big question, you want to become an Educationist or scientist. As an educationist you will be mainly in teaching stream but you can also run your research programs.
As a scientist or researchers, you will have more freedom to carry out research projects, then you can work in every aspects of Geology. As an educationist, though you have higher degrees (including doctoral degree) in geology but you will be designated as Reader or Professor. But as scientist in any univeristy or research organizations, your designation will be Geologist.
You can also work with some oil exploring companies in middle east region, where you can earn lot of money and there your diploma of masters degree will be sufficient.