Is there any saying about "Bindi" anywhere in the Qur'an or hadith?

I have a very strange question according to what my title says. This was confusing me for a very long and it's unclear to me. I just kept myself away from researching about it. However, I came across a situation where one of my office colleague's who's a Muslim and his wife was using a sticker on her forehead (known as "Bindi ", if that's what its called). I didn't wanted to embarrass them asking such strange questions. In fact, I have very little knowledge regarding this. So, my question is; Does the Qur'an or hadith specifically mention about this sort of scenarios? If so, please provide me answers with references. (Image source: )