Rating agency Crisil has lowered the value of bank loan rating (BLR) of ten Indian diamond and jewellery manufacturing companies and reaffirmed its rating on 14 others.%%Shreeji Jewellery, Shreeji Jewellery Designs, Fine Jewellery Manufacturing, D.A. Jhaveri, Kama-Schachter Jewellery, M Suresh Company, M Suresh Jewellery, Mohit Diamonds, Rosy Blue (India) and S Narendra are some of the companies which have been downgraded.%%The jewellery manufacturers whose rating has been reaffirmed are Tribhovandas Bhimji Zaveri, Joy Alukkas Traders, Su-Raj Diamond Industries, Su-Raj Diamond and Jewellery, S Vinodkumar Diamonds, Star Rays, Radium Creations, PC Jewellers, Jasubhai Jewellers, H Dipak & Co, Forever Precious Jewellery and Diamonds, Blue Star Diamonds, Aurostar Jewellery and Arjav Diamonds.%%Crisil believes that the challenging operating environment for cut and polished diamond players will keep sales volumes and profitability under pressure.