Q:

What is the English word for the stones used in Indian weighing balance?

There are stones of 1 kg, 500 grams, 100 grams, or 50 grams used in weighing balance. What are they called in English? 
These weighting stones are normally used by vegetable vendors.

A:

They are called "scale weights" or just "weights". You have a 1kg weight, a 500g weight, and so on.

A:

These are termed calibration weights (also reference weights) as illustrated and described here. 
They are usually sold in sets, enclosed in a felt-lined box supplied with tweezers so as to avoid disturbing the calibrated weight by getting fingerprints on the weights.

Calibration weights are known masses such as a 100g or 500g weight.

