My bath has porcelain tile with an accent wall of calacutta gold. We are at the point of installing the shower curb, window sill and niche base and shelf. I got a quote for $900 to fabricate and install in calacutta marble. It seems very high for a few small pieces of marble (note I am in NYC though). An alternative would be ceaserstone in linen which seems to match both the marble and tile, but doesn't come in the thinner slab needed for the niche (that's what contractor explained to me).

My questions: I am not sure if mixing to save a few hundred will look right, and I am wondering if there might be a better source. I tried two other stone places in NY and their quotes were even higher. Is that just the continuing luck of living in the city?