A type of candlestick pattern that is formed when the opening and closing price of the underlying asset are equal and occur at the low of the day. The long upper shadow suggests that the day's buying buying pressure was countered by the sellers and that the forces of supply and demand are nearing a balance. This pattern is commonly used to suggest that the direction of the trend maybe be nearing a major turning point.
After being down earlier, the market finished up, forming a hammer. Gravestone followed by a hammer. That means ... (who knows?)