Yes, there can be color variations in the Hoktemberyan Tuff of Armenia. The tuff is a volcanic rock formed from the consolidation of volcanic ash and can have different colors depending on the mineral composition and environmental factors during its formation. Common colors of Hoktemberyan Tuff can range from brownish to grayish, but variations may also include shades of red, yellow, and even green due to the presence of different minerals and the effects of weathering and alteration processes.