The redish color of #3 looks familiar, but the texture does appear sedimentry. Remember that although volcanos are built in layers, you're not likrly to see near horizontal layering on the inside of the volcano unless it has been y eroded. Then you are more likely to see breccia slopes than bare rock layers. the 'sand' that you are likely to see would be similar to the color of the rock but perhaps more monocolored perhaps greyer or browner(unless it is wind blown.) There is the Hawaian type(Magnesium rich- darker more flowing) and 'continental' type(Aluminum rich - lighter more explosive.) It is not only the type of volcano but the age of the eruption that counts. Over several eruptions the mineralogy can change. Around Mexico city there are some good examples of the later type. I think post number 7 is getting close except as has been noted about the color of the 'sand' and lack of any breccia(angular boulders). also I noticed when I visited Cerro Colorado(an inactive volcano(?)) in Sonora there were a lot of barrel cactus and other desert plants. I think you're doing an exceptional job with this. Like to see it with the dragon in the pict too when he's done. - TJ