On a trip in 2013, I returned with my daughter to Torres del Paine National Park, we went trekking along the side of the Grey Glacier, and I noticed the combination of the polished rocks that were once covered by the glacier and the grey-greenish colored water of Lago Grey.
The lake has the grey tinted to greenish color due to the the abrasion of the glacier charge over the rock, that create rock powder. Since my first visit, where you could see glacier ice today, it has retracted a long distance leaving only the rocks shown in this image. Today walking tours you could do to the right side of the glacier are not feasible due to the risk. The tour guides are taking you on a small Zodiac boat to the left side of the glacier.
Will try to return some time in the future to do a walking trek over the glacier and photograph the ice on a Moulin. A trip this is pending for a few years, which is now easier to do, as their are direct flight in summer to Puerto Natales, 4 hour drive from the park.