sandal-wood rosary

 Is there anywhere written or told by any holy people or saints that sandal-wood rosary is very powerful?

I have not heard. Answering the question from the perspectives of faith and devotion, the rosary receives its significance from the life of Jesus and Mary, and in turn our own lives in relation to their lives. Devotions receive their merit from the grace given by Christ, not by any magical power of a devotional object or special power of any prayer. A blessed object has its blessings from God, not a 'power' of its own. Certain devotions are formed as though the water, oil or a statue has some magical power. This trend has also influenced our understanding of the Eucharist. Instead of a rich mystery of life in which we are to participate, we have made it a devotional object, a magical power source. Grace acts as we are open, and it asks for a radical conversion of heart to do and think good and to build 'a civilization of love.'