A high-quality essential oil typically has a detailed label with information about the plant used to make the oil and how the oil was extracted. The label should list only one ingredient and not contain the word ‘fragrance.’ The company should be reputable and provide details of third-party testing, including gas chromatography and mass spectrometry, to determine the essential oil’s quality.A high-quality essential oil typically has a detailed label with information about the plant used to make the oil and how the oil was extracted. The label should list only one ingredient and not contain the word ‘fragrance.’ The company should be reputable and provide details of third-party testing, including gas chromatography and mass spectrometry, to determine the essential oil’s quality.