Price Prediction Of Diamonds

I used Decision Tree, Random Forest, Linear, K-Neighbors and XGBoost Regressions with Python. I chose the best model with the Cross-Validation method. I used the R-Squared method to check that it gives a consistent result. As a result predicted with nearly 99% success rate. There is no 'Overfitting' problem.

I used the 10-Layer Cross-Validation method. The results are below:

It is XGBoost that works best in these datas. I used this regression model for prediction.