Gelest, Inc. (Morrisville, PA), which makes customized, highly specialized organosilicon compounds, metal-organic compounds, and silicone materials, has partnered with New Mountain Capital, LLC, a New York investment firm that currently manages approximately $15-billion in assets.New Mountain identified Gelest through its focus on the life sciences and specialty materials sectors, and will provide significant financial and strategic resources to support future growth initiatives and better serve its customers. “New Mountain is the ideal partner to help Gelest execute on its growth plans,” said Barry Arkles, president of Gelest.  “New Mountain is known for its focus on business building, and Gelest will have deep resources at its disposal to help us achieve our strategic growth objectives.  We look forward to our partnership and the benefits it will yield for our customers and employees.”