Tax Question-Giving ownership in a company

A person I met recently started a company to and gave 1/2 ownership to a person he knows who has extensive experience in the business. The major asset the company started with was a quarry purchased for $500,000. What is the accounting for the start up of the company. What are the tax implications for the party that was given 1/2 ownership in the company and how can any tax impact be minimized.