Very upmarket rosin made with gold or iron (others are available but these are all I have)
maker's description: The ingredient Gold gives the LARICA Metal Rosin an especially balanced characteristic. The tone is full, harmonious, round, warm, voluminous, and at the same time, radiant and clear. It is most suited to give the instrument a variety of colorful tones.
The addition of Meteoric Iron brings forth a powerful and shining tone. The quality of sound in comparison to the Gold is more focused and energetic. This Rosin is favorable for solos because the tone carries well over long distances.
The scale of hardness for rosin ranges from I-VI, hardest to softest. For most instruments, there are two grades of hardness to choose from. The softer grades essentially help the hard and sharp sounds of an instrument produce a milder and nobler tone quality. The harder grades can bring more clarity and exactitude to a softer tone.
For violin, choose 1 for hard and 2 for soft
For viola, choose 2 for hard and 3 for soft
For cello, choose 3 for hard and 4 for soft