- Barite 4.2g/ml - Barite 4.1g/ml. Bentonite. Drilling grade - API Specification 13A Section 9 - API Specification 13A Section 19 (OCMA grade Bentonite) Calcium Carbonate. ... (Locally Manufactured in Oman) Fertilizer Industry. Bentonite Fertilizer grade (Locally Manufactured in Oman) Civil Construction Industry.