What is Islam's ruling on a woman refusing to shake hands with another woman because the latter is wearing gloves?

A woman must cover her hands with gloves, especially if they are adorned with henna, and it is impermissible for her to expose them in front of non-mahram (definition) men. As for the prescribed greeting (al-salamu alaykum), it is sunnah (definition) to initiate it and obligatory to return it, and it is sunnah to spread it among Muslims. Shaking hands should not be abandoned due to the reward it entails and its role in fostering affection.