I hope I’m posting in the right place. We have flagstone coping and some of the material between the stones is cracked. I chiseled out a line assuming it was grout but it seems much harder than any grout I’ve used (for tiles). If possible would someone be able to attempt to help me identify the material? Pics included.![3FC2DCE5-C038-4B2B-A378-561DECC8F50A.jpeg 3FC2DCE5-C038-4B2B-A378-561DECC8F50A.jpeg](https://www.troublefreepool.com/data/attachments/148/148176-c7f07d99c1f18b1ef30bfe539f79d79e.jpg)
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![7A13A0FF-FD60-49DB-BF60-A68181F3BC56.jpeg 7A13A0FF-FD60-49DB-BF60-A68181F3BC56.jpeg](https://www.troublefreepool.com/data/attachments/148/148178-6153388a3dba66d312a4ac5198343618.jpg)
![3FC2DCE5-C038-4B2B-A378-561DECC8F50A.jpeg 3FC2DCE5-C038-4B2B-A378-561DECC8F50A.jpeg](https://www.troublefreepool.com/data/attachments/148/148176-c7f07d99c1f18b1ef30bfe539f79d79e.jpg)
![91170D00-4882-4B31-8DA8-588B314281B6.jpeg 91170D00-4882-4B31-8DA8-588B314281B6.jpeg](https://www.troublefreepool.com/data/attachments/148/148177-09df391ab8d0157d5345dc9b1b64ce67.jpg)
![7A13A0FF-FD60-49DB-BF60-A68181F3BC56.jpeg 7A13A0FF-FD60-49DB-BF60-A68181F3BC56.jpeg](https://www.troublefreepool.com/data/attachments/148/148178-6153388a3dba66d312a4ac5198343618.jpg)