It grows in my frontyard. I'm not sure if it's called lime because the skin looks wrinkly.
Lime mortars have slaked lime, sand and water (in various proportions) as you have stated. You can make a mortar out of just slaked lime, but it takes a very long time to prepare and harden and it is not often used today. The mortar with sand will harden much quicker and is most used lime mortar used today. My house was built in the 1800's and had lime mortar, so I use it for repairs. Most new construction, however, uses a harder cement based mortar that needs the harder bricks used today.
