Diamond / angular

Overview

Diamond-shaped reports are less common than disc or triangle descriptions. Viewing angle can change the apparent geometry, particularly when witnesses see only a night-time silhouette.

Reported angular forms

The Cash–Landrum shape claim has a traceable testimonial basis. In the reproduced transcript of the 17 August 1981 Bergstrom interview, Betty Cash describes the drawing she is making as diamond-shaped. An officer then shows it to Vickie Landrum, who agrees with its approximate shape. This preserves two witnesses’ agreement in a joint interview, rather than two independently produced drawings. The available transcription also acknowledges limitations in reproducing the tape; inspection of the recording and signed drawing would strengthen the comparison. Bergstrom interview transcript

A diamond description can refer to a projected outline, a bright area or a comparison with a familiar geometric shape. Corners and edges carry more geometrical information than the category label alone. Agreement on that label is relevant to the reported appearance, while the medical aftermath concerns a separate causal question.

The Ministry of Defence logs preserve the term across several dates, including an entry allowing either a triangle or a diamond. Those summaries establish that angular language was reported. Their brevity prevents reconstruction of the surfaces, viewpoint or dimensions that would make the two categories physically distinct. UK Ministry of Defence UFO Report 1997

The PR28 description

PR28’s mission-report wording uses a diamond comparison, while the release’s image description uses an inverted teardrop comparison. The discrepancy places the classification at the level of descriptive interpretation. A shared official source can preserve different shape judgements without either being a measured physical outline. PR28 release

The image should therefore be examined for which boundaries belong to the target and which arise from contrast or a trailing feature. A label in a mission report can guide that examination, but the visible frame and the report need separate treatment when their descriptions differ.

Outline and causal attribution

A four-cornered silhouette can change as an object rotates or as bright and dark areas become visible. Independent viewing positions or a stable sequence would help distinguish a plane outline from a three-dimensional body. A later reconstruction that regularises an uncertain outline supplies an interpretation rather than an additional observation.

Reported health effects need their own chronology, medical documentation and exposure hypothesis. Even a securely recorded illness cannot determine a preceding object’s geometry. Keeping the shape claim and the causal claim separate allows each to be evaluated against the evidence relevant to it.

Report catalogue

Selected records describe reported appearances. Cross-listing one event under several forms adds no independent observation.

Diamond / angular report catalogue

1 record

Case	29 November 1989–April 1990 · BelgiumBelgian wave triangular-form reportsUnresolvedOfficial archival guide to the Belgian military record
Summary	Civilian and police witnesses reported dark triangular or delta-like forms with corner lights, central illumination and slow or hovering movement. The Belgian Air Force statement documents the later F-16 response. Those radar contacts occurred separately and provide no evidence about the shapes described in the visual reports.
Core evidence	Morphology confidence Moderate Physical form Probable body in selected reports Form Triangle or delta with three lights in selected reports Movement Slow translation, hovering and rapid departure reported Evidence Witness statements, police records and military documentation Limits Strong morphology in selected reports; the series is heterogeneous
Finding	Selected visual reports describe a coherent triangular form; the later radar episode is a separate evidence stream. Case deep dive Public record Wilfried De Brouwer Belgian civilian witnesses

Evidence assessment

The angular category is supported by witness terminology and an official release containing divergent shape descriptions. Those records preserve a real classification problem: the word diamond can identify an outline without determining which part of an image or body produced it. PR28 makes that distinction visible within one evidential chain.

Agreement on a diamond label has to be assessed within the procedure that produced it. Cash and Landrum’s joint discussion of a drawing cannot establish how closely two independently recorded outlines would have matched. PR28 raises a different issue: divergent descriptions within one release show that classification can vary without any change in the underlying observation. These two cases locate uncertainty at different stages, witness comparison and image interpretation. Additional uses of the label would add little unless they preserved the boundaries and viewpoint needed to resolve those uncertainties.

Cash–Landrum’s reported shape and medical aftermath require separate assessments, and the brief official logs add terminology rather than independent verification of its body. The selected corpus supports comparison of angular appearances. It supplies too little shared geometrical information to infer a common construction or causal mechanism.

Research gaps

The earliest Cash–Landrum shape statements alongside their drawings and separate medical chronology.
Original PR28 imagery and sufficient recording information to compare the mission and image descriptions.

Cases and witnesses

Case deep dives

Cash–Landrum incidentWitnesses described a bright diamond-like object and later reported medical effects.

Witness deep dives

Betty Cash Vickie Landrum Colby Landrum

Public record

Official material, where available, is linked in the source library.

Source library

The tiers describe each source’s relationship to the record. Direct testimony can remain uncorroborated, and an official document can preserve a claim without verifying its physical interpretation.

Tier 1 Primary records and testimony

Cash–Landrum: Bergstrom interview, 17 August 1981 — CUFON’s transcription of a recording supplied by Betty Cash, reproduced by Patrick Gross. It preserves the shape discussion and joint drawing procedure; the recording and signed drawing require separate inspection.

Tier 2 Official and institutional records

DOW-UAP-PR28, Unresolved UAP Report — A mission report used the term diamond-shaped, while AARO's imagery narrative described an inverted teardrop. The difference remains unresolved.
UK Ministry of Defence UFO Report 1997 — Four dated entries use diamond language, including one that also allows a triangular description. The log provides no findings on identity or geometry.
UK Ministry of Defence UFO Report 1998 — Three dated entries use diamond language; the log supplies no supporting investigation material.

Editorial record

Published 1 October 2026Last revised 5 October 2026Next review 31 October 2026